Never try to rationalise D&D economics. They don't work. The game provides rules for adventurers, but those rules absolutely do not attempt to address long term economic factors. You may as well start worrying about how treasure rewards destabilise entire regions, or how the predator/prey ecology of monsters doesn't work.
The NPCs don't do that. If a PC wishes to make that his game, he isn't really playing D&D.
The NPCs don't do that. If a PC wishes to make that his game, he isn't really playing D&D.