I am one of the resident LP enthusiasts, and the author of the pianists on vinyl thread you reference. Briefly, I started collecting them in 1990 when everyone was getting rid of them. In the late 80s, I actually jumped on the CD bandwagon like everyone else. However, one day upon playing an old LP we had in the house, I found I preferred the sound of LPs in many ways--to say nothing of the tactile pleasures of the disk itself and the covers, liner notes, etc.
Back then I was an undergrad and worked on Saturdays at a book/record store, not so much for the money, but to get my hands on the vinyl everyone was bringing in and selling. However, in nearly 30 years of collecting, my collection remains relatively small and manageable at about 1200 LPs (and about as many CDs). This is largely because I have been picky about condition, and to a lesser extent, some of the minutiae you reference (I avoid pressings from certain labels in certain time intervals)
Obviously, there are many great performances from the LP era (roughly 1950 - 1990), but the sound quality is another issue for me. The debate about CD vs LP quality has been hashed over endlessly, and to the extent people disagree with me, I say GREAT--more for me!

Clearly, there are advantages with CDs over LPs, and advancing technology (to a certain extent independent of format itself) has yielded important advances over the years--stereo, increased dynamic range, increased frequency response, etc., etc. AND YET, to my ears, there is something special about vinyl--an immediacy, a warmth (call it distortion if you want, don't really even care), and other qualities that are hard to describe. One such quality is the presentation of the acoustic envelope around the instruments--so many CDs to my ears are quite dry and sound as if the the musicians were recorded separately and overdubbed--harmonically dead!
I have extraordinarily sensitive hearing (my ENT, who has practiced for decades was floored by it when he tested me), and I have also invested a fair amount of money over the years in playback equipment--turntable, tonearm, etc. And yet, I don't really consider myself a "golden ears" audiophile. I care about the music first and foremost, and don't have unlimited funds or patience to endlessly futz around with equipment.
I have become interested in certain labels over the years, partly because of their sonic attributes. I am fascinated with the Westminster label, especially from the 1950s. Also Period, Columbia, etc from that same era. Despite all of our advances in recording/playback since then, the sound from this era is very compelling to me and other collectors I know. These were especially compelling for small ensemble, chamber, piano, voice, but not so much for organ or orchestral, for which I do often prefer more modern recordings, or even CD. As a pipe organ enthusiast, I do think this is one case in which I prefer CD, generally.
Vinyl has been coming back in a big way over the last decade or so, and it cannot be entirely due to teh much-maligned hipsters. Vinyl enthsiasts are a very diverse bunch, from classical and jazz lovers like me, to 19 year-old kids who like indie rock and don't even own a turntable (some buy the disk and download the MP3). It will never be what it once was in terms of volume, but it is certainly interesting to visit a brick and mortar record store these days. It is as if time is running in reverse ad the LPs are eating up more and more space once allocated to CDs.
Nevertheless, as a busy person, I often don't want to mess with the LPs themselves, which is why I digitize them on a regular basis (about one a week) and listen mostly on my computer or headphones, or larger system. THe special LP qualities still seem to come through on digital (although I use a higher sampling than 44.1, etc)
As for collecting, I have too much music to listen to if anything, especially on CD, where I have many large sets with many disks I have not even heard yet. I enjoy augmenting my LP collection by picking up a disk or two here and there from eBay or a brick and mortar store. But, it is a luxury, not a necessity. I like to compare it to my watch fascination--sure I could buy a $20 Timex quartz that would keep better time than my mechanical pieces, but it is just not the same!