There are so many controls given the player to 'balance' their own world economy, why would you want the devs to implement a one sized fits all solution that may not fit many people's play style? In a single player game?
Without touching the extremes, and I would agree it's a pretty lame response to say something like - well, just throw your gold away or spend it on stuff you don't need - let's talk about pretty easy, non-invasive means to set the kind of economy you want that fits right into the existing game world without you needing to do bizarre things like spend your gold pile on runes and then throw the runes away to pretend you never had that gold. No mod needed either although there is a mod that can significantly reduce your gold earned if you want.
1- as noted by others, just don't loot/steal from peasants and houses in cities. Only loot I take from homes are quest objects and the one armor diagram that some odd reason was placed in a private home.
-not only does this cut down on gold you would make by selling all that stolen stuff, but it forces you to spend some gold to buy the alcohol and other misc items you no longer get stealing from homes because you get a TON of consumables from homes. So double win-win if you want a reduced economy - you make less and you need to spend more.
2- Don't go out of your way to sell to the exact merchant type that corresponds to the exact item type.
-We all know if you want to maximize gold, sell armor to armorers, weapons to smiths, hides to innkeepers, etc. Well, another cool way with minimum effort and non-invasive action is just sell your loot gained from combat, quests, etc to whatever first merchant you run across.
-Sometimes this means it will be the optimum merchant, sometimes the "worst" in the sense he'll offer barely half what the "right" merchant would. But this will also significantly cut down on gold build up.
3 - don't bother or waste time harvesting plants, just buy what you need when you craft alchemy - there isn't single plant that you need to harvest that isn't sold by some herbalist or alchemist. Only specific monster parts are the rare component - you can buy everything else, so this is another easy to do, non-invasive means to provide a bit of gold sink on top of the earn less from above suggestions.
4 - use your crossbow, a lot - this one you may not want to do because I realize some ppl don't like the way crossbow works (e.g. not a true archer weapon like skyrim)
But if you don't mind, and you pot shots off all the time, especially exploding bolts to set mobs on fire - it's actually a decent mini gold sink. Not a ton, but again with both reduced income and more expenses like crafting lots of exploding bolts, it's another economy control.
*note - not sure if ppl know but the other than shooting underwater mobs, and brining down flying creatures, in my opinion the true best part of the crossbow is it's ability to mini-stagger a mob. Try it out, even with a non-exploding bolt, it very briefly staggers the mob so that if you fire just as you charge, you can whack the mob free hit while it recovers from the bolt stagger. Best is if the exploding bolt version catches the mob on fire because then of course you get the free pause/stagger all mobs do when set on fire
There are a ton more ways to simply and effectively control your gold input and output levels without any use of mod or bizarre jumping of hoops like throwing your gold away on buying items you don't need and then throwing the items away.
I've started a concurrent 2nd play through just recently where I am doing #1-3 above and it has significantly cut down on my gold supply as well as raised my expense level for consumables. To the point where I have to now be careful what runes I want to buy to upgrade. I realize even this will make end game still a gold snooze but it's sure made early and mid game a heck of a lot different (e.g. really kinda feel poor)
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Did not list this #5 because it's too subjective but I've started doing it in my concurrent "poor" 2nd play through I'm doing along with my still running rich 1st play through - I am NOT recommending it, just saying it's what I do, and if you're like me, maybe will enjoy it too, but YMMV.
5 - Treat consumables as exactly that - use once, toss to destroy it and re-craft your replacement consumable
Crafted potions and bombs can be dropped - game will ask if you are sure as dropping it will destroy it but you can click yes. In my 2nd play through that I limit my economy via above suggestions, I've added my own "death march" mode to the death march difficulty level
Whenever my potion or bomb runs out of charges, I drop it (which destroys it). I completely realize that some of those bombs/potions can only be crafted via some pretty rare items you don't get a lot of, but they are pretty few if you think about it. If you've done the game once, you know how and where to farm all the parts you need, even rare ones like nekker hearts.
For the great majority of the rest though, it uses pretty common components that just costs you to remake - and thats why I do it. It has really added an ultra level of difficulty to my early stage of new DM play through but gotta say it's pretty interesting and adds some strategy to having to save my bombs for key fights rather than just toss them like candy with the recharge via alcohol method.
I'd call this both a gold sink and difficulty dial, but if you thought DM was too easy or not challenging enough, I'd tell you to try this and see how long you say that when your consumables truly are consumables.
