One issue with older versions of D&D that heavily relied on treasure GP is that characters have to become rich to advance so that by fourth or fifth level mundane equipment costs become meaningless. Carousing rules and limits such as the Paladin's tithe have come along to address but I was thinking of going to the source.
Have you ever considered changing the ratio either in a fixed manner, such as 10xp per 1gp of treasure recovered, or a float perhaps based on level, you get 1xp per character level per gp (a fourth level fighter would recover around 4300 gp) or maybe hit dice of monster guarding it (with trap guarded being 1 or 2, maybe more for a serious trap and unguarded being 1 or less).
Edit: This is about speed or about me being someone who started at 3.x...it's about wealth. It was specifically spurred by some musing over at Carcosa (Geoffrey McKinney's now-defunct blog). I'm looking for solutions other than the carousing rule from an early Dragon issue or AD&D style training costs.