I am afraid it is one of those Larian's "it breaks the game but is FUN" things. Merchants have been a joke since D:OS1.
I suppose to some it is "if you don't like it, don't use it", to me: "can't roleplay as a thief or the game falls apart".
Economy often falls apart in RPGs, unfortunately, but here one doesn't have to try hard.
Like only available on Ironman mode or something so it actually has consequences.
Or something that one would have to heavily invenst into, to make it worthwhile. Don't know how DnD 5e works, but in BG3 one of my issues is that every run feels the same. Checks can be brute forced easily even by characters not trained in the field.
