Only have 1500 albums and have quite a few not classical that are gapless. Granted I have a lot of 70s rock and live albums, Beatles and others that used it on albums. I don't know for sure why gapless started disappearing, but it does seem like a lot of modern players from China are digital media players first and CD players second even though they are very expensive. I wanted a new CD player and ended up buying an Onkyo that has been are the market 20 years since it was designed before this trend started. There are others that can play CDs correctly. Yamaha I believe did a firmware upgrade to fix their players. The Panasonic and Sony 4K Blu-ray players I own can also play CDs correctly even though this is a secondary feature.Ah, apologies. I clearly read your post backwards thinking it said early CD's player didn't get gapless right.
I don't have any experience with late model CD players, since around 2005 or so I've only played CD's via the transport in my computer or internal rips of them. Also not being into Classical music, I don't think more than a handful of my 5000 albums are gapless. Why do you suspect modern CD players are ignoring proper Red Book std, that is surprising?