Thanks for the replies -- they gave me plenty to think about.
I don't completely buy the argument about the greater variety of equipment available today. If you only look at the number of manufacturers and products, sure, but at a practical level, it's probably not true. The internet makes it easy to buy products from all over the world, but back in the 1960-70s every moderate sized town had an electronics store that sold hi-fi equipment. Most of these stores were local, but you also had chains such as Lafayette or Allied. You could walk into these stores and see, touch and hear a decent variety of equipment. Effectively I think that matches the virtual variety we have today.
I don't think there is any question that Audiogon, Craigslist and eBay have altered the economics to make buying/selling used equipment vastly easier for the consumer.
I also think magazines/reviewers play a crucial role. Back in the day the magazines only really talked about how components sounded in the most general sense. Terms such as full bodied, lush, rich, tinny or boomy were used. Notice how even a non-audiophile could understand these terms. But with the rise of subjective reviews the vocabulary changed and simply descriptions of sound were replaced with "concepts" about sound. Terms such as soundstage, ying/yang, high resolution, musical, hi-fi sounding, inner detail and finally, my favorite, continuousness came into use. Non-audiophile have no idea what we're talking about anymore.
All the talk about sound gets in the way of enjoying well recorded music reproduced over high quality equipment. Instead of pursuing this relatively simple goal, audiophiles have got caught up in chasing the description of how their systems are supposed to sound. Are you lacking soundstage depth? Missing resolution as notes decay into the noise floor? No imaging beyond the outer edge of your speakers? Is the soundstage space between performers not fully fleshed out? If your system suffers from any of these "problems" then obviously you need to upgrade. Magazines have purposely or not developed a world view and vocabulary about sound that plants dissatisfaction in audiophile minds.
It's actually a testable hypothesis. If you stop reading about sound, will you slow down upgrading.