Actually, millennials were the reason there was an uptick because it was what the cool kids were doing because it was not mainstream. Truth is, that probably hurt the cause more than it helped.
I think there's some truth in what both of us said. It was millennials who
were said to be interested in turntables and vinyl records because they were
vintage. I believe there was plenty of lip service paid to this idea, especially the vintage part, but not enough money was spent to make it a reality. Having a turntable also required having a receiver or preamp/amp. Those same people who liked the vintage fashion found it to conflict with their desire of avoiding the bulkiness of older audio electronic gear.
All this talk has made me just a little nostalgic. I do not collect turntables or cartridges, it really is 50-year-old technology. However, I do still own and occasionally use that AR turntable I mentioned above. When my son was teen aged, he destroyed the cantilever on the original Shure M91 cartridge. I replaced it with a Japanese-made Sumiko Oyster. It was fairly inexpensive in the late 90s (about $60), and more importantly, it was available when I looked in a nearby (now long gone) shop. I never did know if it made an audible difference or not compared to the old Shure M91.
When I first bought that rig, I was out of college for about 2 years at the time, and my entire experience with turntables & cartridges was what I saw while in school. Everyone seemed to have either a Garrard or Dual turntable, and the Shure, Pickering, or Stanton cartridge that came with them. There were other brands of turntables (if I encountered any I don't remember it), but I never saw other makes of cartridges. No one I knew played the game of switching cartridges and listening for differences. It was just too difficult to switch them.
Years later, during the so-called vinyl revival, I was amazed to see the large number of cartridge makes available on-line. How can a fading technology have so many cartridge makers? Who buys this stuff? I wonder who has ever switched out cartridges, and who kept using what originally came with their turntables? I’ve switched only once, and that was out of necessity. I could be wrong, a few of us may very well have done this. TLS Guy probably can lead that charge. But is it common or uncommon?