The thing is that “gold” in D&D is just some abstract indicator of value and we can just assume that in this fantasy universe, gold is cheaper and less scarce than in our own. Same with the arbitrary relations between gp, sp, cp and pp (and the less common ep). Given that the rulebook (at least used to state—I don’t know if it still does) that a coin had a weight of 1/10 of a pound, the contemporary value of a gp would be high in any real-world scenario (around $3800 according to the first site I found that would give me a number).

That said, I remember reading either in one of the old AD&D rulebooks or maybe Dragon magazine that GMs should consider the idea of adventurers showing up in town with sacks full of gold and loot being the impetus for an inflationary moment in town as all this new money enters the local economy. One could even imagine the townspeople being resentful of their food prices rising thanks to these interlopers showing up with all their gold and this being the impetus for its own little mini-adventure (perhaps even a quest for your players to boot a different bunch of adventurers out of town because they’re making things too expensive for the locals).