But if you can't buy or otherwise accrue most of the things a typical party is going to want / need by games end then the whole process of loot becomes equally worthless doesn't it?
Since you accrue a lot of stuff through questing/looting the typical party has all the stuff it needs. And for the price of the best item you can buy 5 items that are just a tiny bit worse.
Why do you declare bancruptcy because you only can afford to either A) substitute your sword of uber 6d8 +1d6 cold with a sword of uber 6d8 +1d8 cold or B) your ring of almeighty with a ring of almeighty +1HP ?
And if the loot is there and the packrat player grabs every last bit set out for him shouldn't he be able to benefit at a higher level from it than the player that left the bulk of it on the ground?
Many players explore every corner of the game world without being packrats. Frankly I don't care what a packrat can buy by games end. I assume the game will be balanced for normal players who may explore from 33%(?) up to 100% of the game world and those players should not be buried in gold. They should still like to open a gold treasure chest because the gold has value for them. And as soon as they can't buy anything anymore because they bought everything worth buying that feeling is gone. At that moment gold becomes worthless.