I feel like this is more of a D&D problem than an an RPG problem more generally. Let's use D&D as the stand in for games of it's type, just to be clear. The game provides you a very granular spending resource in GP, and a bunch of ways to spend it. Some of those ways, like new gear, have obvious beneficial in-game consequences, while others, like our fabled exemplar hot bath, do not. Players who inhabit the squalid huts on the very end of the gamist spectrum only want to spend in-game resources on things with tangible in-game benefits. Despite my light mockery, that's fine if that's their table, whatever. I find it unappealing and unfulfilling, but whatevs.
As has been mentioned upstream, some games dodge this issue in a bunch of ways. Keeping our focus on D&D for a moment though, I think it's a function of the table and the players, not so much the game. I'd bet those same players would roll their eyes if their DM tried to deny them service at the fancy armorer because they looked like a bunch of dirty ragamuffins. I would probably address this general idea as part of session zero. If the table wants to hand wave it that's fine, but if they want to play it to the moist, soapy, hilt that's cool to.
As has been mentioned upstream, some games dodge this issue in a bunch of ways. Keeping our focus on D&D for a moment though, I think it's a function of the table and the players, not so much the game. I'd bet those same players would roll their eyes if their DM tried to deny them service at the fancy armorer because they looked like a bunch of dirty ragamuffins. I would probably address this general idea as part of session zero. If the table wants to hand wave it that's fine, but if they want to play it to the moist, soapy, hilt that's cool to.