I believe the pursuit of perfectionist audio is different than perfect audio. One is an end and the other a process. Rephrasing my OP, when did we go from an end, purchasing good/better/best audio equipment, to a never ending process, the pursuit of perfectionist audio?
I would have originally thought it coincided with the rise of subjectivist reviewing, but the link with spreading internet use is undeniably a factor. A site like Audiogon allows a person to benchmark himself vs. other audiophiles. In a consumer oriented society keeping up with Joneses is a powerful motivation. Then there's the constant barrage of "something new has just transformed my system" posts. And finally there are the posts where people tell you outright that it (presumably the hobby) is a journey and that the journey should be enjoyed.
WARNING! WARNING! CAR ANALOGY COMING...
What part of owning a sports car is enjoyable? Doing the research, test drives, negotiating the price, insuring it, waiting for delivery, reading the owner's manual service recommendations or driving it on a winding road on a beautiful day?
My take away from this incredibly insightful analogy is listening to and enjoying music is several orders magnitude more rewarding than messing around with equipment.