With the recent hotfix, everything price is down to almost nada again. Recyclable gold is still a thing but 4x thievery after level 5 is all you really need to break the game again.
Maybe so, but that sounds like a case for tweaking Thievery and possibly making it much more difficult for NPC's to be stolen from a second, third, fourth time. That makes sense, since if you get stolen from once you'll probably be more on your guard, hence the difficulty will increase. That will keep Thievery useful without making it TOO broken.