I missed this thread a few days ago, probably because I was busy organizing my duplicate LPs to sell at the local record show. I'm not a regular dealer kind of guy, I just find records I like for cheap and redistribute them for just slightly-more-than cheap and keep whichever is the best sounding copy for my collection.
If this last show was any indication, vinyl hasn't peaked yet. I sold a ton of records and gave out a bunch of cards for turntable repairs. What is encouraging to me is that most of my customers were in their 20s or younger. And I don't think they were hipsters, and they certainly weren't audiophiles (note -- audiophiles are just hipsters with different sets of rules). They seemed to me to be people who get really passionate about the music they like and really enjoy owning the artifact. Nothing will ever replace an album cover for tactile experience, and even a cheap turntable and a cheap stereo is going to sound better than laptop speakers or consumer-grade earbuds, and that's what the younger crowd grew up on.
It amuses me to hear reports that the people with higher-end gear are having more trouble enjoying vinyl. Good gear should make your music sound better, not worse!
My guess is lots of them dipped their toes with entry level Music Halls or Pro-Jects and got turned off because those just don't sound that great, and then had to spend gobs of money to get something better. And it was still an "inconvenient" format. Oh well.
The current vinyl wave will peak eventually, I'm guessing in the next five years. But a decent chunk of the people just getting into it now will remain into it. I also think people will still be pressing records for the foreseeable future because the LP issue will be the "collector's edition" of a piece of music. People like music and they like collecting things. That's human nature regardless of trends.