I was listening to Episode 11 of Improvised Radio Theatre with Dice, and was struck with a new D&D premise that I'm going to scrawl down while I can remember it.
The topic that was brought up was economics - specifically, how the gold price crashed in Spain when looted gold was hauled back by the ton from South America, coupled with a remark about how when governments feel hard-up, they tend to cut spending and consider starting a war. This was put into context with the way adventureres haul gold out of dungeons, which should really destablise economies in much the same way. My brain rattled around briefly and then settled on an idea: what does this do for adventurers?
First thought: adventurers rarely seem to have any clear social context, perhaps because they only make sense in a reality where some people can be superhuman and there are enormous monsters. Historically, my impression is that wealth was not only tied to social status, but actually restricted by it. Sumptuary laws determined what people could wear, the form of tombs, expenditure on food and so on. People determined to perpetuate social hierarchies carefully crafted laws to maintain their status, forcibly distinguish social groups, and in some cases to seize money from the wealth-generating middle class to keep them from getting uppity.
Also, governments tend to like controlling money. Adventurers often seem to be rather disreputable sorts from quite humble backgrounds, excepting some wizards, some priests and the odd long-lost royal heir. Few kingdoms can readily stomach the idea of a bunch of violent nobodies bursting onto the scene with huge piles of gold they've (allegedly!) dragged out of some old ruins, destablising the economy and giving people ideas.
Think about it: lotteries are bad enough. This adventuring business says "why not chuck in your poorly-paid and dangerous life as a serf/builder/sailor/soldier/tanner, learn to swing a club around, and take up adventuring? You too could find vast piles of jewels lying around!" Given how bad life was for a lot of people in history (quite a lot of whom were conscripted into fighting regardless) it's really a pretty good alternative. Governments won't like this, because it encourages vital parts of the labour force to go into adventuring.
Also, just in general, speaking as a government: my attitude towards professional killers with vast amounts of wealth who are lauded as popular heroes is not positive. The term we use here is "threat". People might get the idea they'd be a better government than I am, and start some kind of popular rebellion. They might use their newfound wealth and popularity to burst into society and upset the delicate web of marriages, treaties, bribes, threats, debts, favours and habit that maintains our kingdom in relative peace for at least a proportion of the time. They might try to make us a series of offers we can't refuse, and whether these are generally benevolent or selfish, that interferes with normal governance. Or they might hire a load of mercenaries and overthrow us.
The obvious solution to these problems are to take that money away pronto.
We already do this. Treasure Trove laws are a thing, and easily expanded. If you find a load of lost elven treasure lying around, congratulations! The treasury will very happily take all of it, give you a small reward, and put your name on a plaque somewhere. If you kill a wyvern containing valuable organs, congratulats! All wyvern corpses (but not live wyverns) are the property of the king, and you cannot trade in their organs. If you slay a horde of bandits, congratulations! Whatever of the property cannot be reunited with its rightful owners is the property of the king.
Secondly, assume inspections are a thing (tax inspectors are real, y'know). People can't just go around with lots of money. If a party of adventurers crosses into Duke Clutchful's lands, they'll be closely questioned about the ten sacks of gold they appear to be carrying. Not being nobility, they clearly have no lawful means of obtaining ten sacks of gold (since anything they loot is treasure trove, remember?) and it will be confiscated.
There's ways around this, of course. The simplest is to bribe your way into the nobility, either with gold or with acts of violence: this is how basically 100% of people have obtained titles throughout history. As a noble, you're perfectly entitled to own ten sacks of gold. Of course, you're also obliged to maintain a house in the capital where you spend six months of each year; to contribute substantial sums to the exchequer; to provide a number of soldiers commesurate with your status whenever a war happens; to heed royal proclamations about who you're going to marry; to host the royal court at vast expense when they choose to visit; to maintain estates where the royals can come and kill all your animals; and so on and so forth.
Adventuring in a World Gone Bust
So let's get back to that early point about social context. The second idea I had is more about why people are adventuring, and it's not an idea I remember seeing anywhere. In short: poverty.
So let's imagine that Kingdomia is a sort of cross between Imperial Spain and 1920s America.
Kingdomia has everything going for it. During the great wars of the last decade (probably involving some kind of dark lord), Kingdomia was safely hundreds of miles away, and the only powerful nation in its corner of the world. While empires fell and great houses burned, Kingdomia offered subtantial loans, traded with the nations it wanted to win, sent some soldiers along, and consolidated its own situation. Its economy swelled as it became the only major trading nation not bogged down in a vast war, becoming the dominant market force and gaining political influence too. Technological and magical breakthroughs made for the war effort span out into useful advances for daily life. For the people of Kingdomia, life was on the up.
It watched the war, built up its own armies and prepared carefully.
Kingdomia's forces finally joined battle at the tipping-point, hurling overwhelming military and economic might into a conflict between battered nations ruined by the war. They crushed the necromantic hordes, won much of the glory, and rampaged through enemy lands in an orgy of looting. Territory was claimed, prisoners taken, and vast wealth brought forth from the shadowy dungeons of the dark lords. Exhausted allies were grateful for the intervention, and too weary to contest the terms of their victory.
As thousands of soldiers returned home, Kingdomia experienced a sudden flowering. Gold and jewels poured into the economy like water, exhuberant veterans burning money on sweethearts, families, and sweet little farms with white picket fences and giant rats scuttling round the kitchen door. The end of the war meant a resumption of free trade with dozens of nations, and a flourishing business in helping them rebuild. Money poured out of other nations and into Kingdomia.
Within a few years, the value of gold was plummeting and Kingdomia at a standstill. Thousands of soldiers found no real jobs to return to, and promises of good housing for the heroic troops were broken. The ruined nations were in no position to buy goods from Kingdomia as they painfully put themselves back together, and struggled to ensure it wouldn't happen again any time soon. Businesses constructed on the back of the war effort fell apart, leaving thousands out of work. Trading partners who were mostly client states during the war feel it's safe to reassert themselves again and insist on more independence; nobody can argue now that it's "aiding the Dark Lord!". And large families born during the boom times have grown up and found nothing to do.
Shanty towns are growing throughout Kingdomia. People are desperate and hungry. The wealthy struggle to maintain their position. Social changes are afoot, and barriers breaking down. A homeless wanderer, an unemployed veteran and a wizard whose guild fell apart can easily find themselves in company at a cheap inn. There are still monsters scattered across the world, left behind by one side or another in the shadows of war, and many of them were once human. There are precious things to be found everywhere, and precious few people to care who takes them.
Why do you adventure? Because you took a good, hard look at the world around you and realised it's your best chance at a better life. Better to fight goblins and seek treasure in the deep mountains, than slowly starve in the city. Because you came back from the war trained to kill, and your country threw up its hands and declared it didn't know what to do with you. Because when gold is worth less than silver, the only way to feed yourself is to go for the biggest treasure, wherever that may be. Because maybe if you can bring back something worth something your family won't go hungry, and if you die in the swamp then it'll be one less mouth to feed.
The government, meanwhile, is quite happy for you to take yourself off and (with any luck!) get yourself killed in a hole. If you come back with valuables, hoorah! - they'll take most of them off you to help with that economy problem. They're not going to keep a very close eye on you, because there are a LOT of marginal people around and a lot of low-level crime, and particularly if you seem to be solving problems, rather than causing them.
This seems like a situation where becoming a professional adventurer might make a degree of sense. It doesn't have to be the current phase of the setting, though - you could easily say that you became an adventurer ten or twenty years ago to survive in that economy, and although things have improved since then, now it's your profession and you're good at it.