I think Sony only have one plant left (in Austria) pressing physical discs.
Vantiva (formerly Technicolor) are the biggest players but have just announced they’re unloading their Supply Chain Services division, which includes their disc-pressing plants, to private equity.
Blu-Ray (both HD and 4K) is obviously a niche product now but there are numerous boutique labels doing great licensing work. It feels in a healthier place than it did a couple of years ago when the streaming wars were at their height.
It’s a bit like a return to the Laserdisc days of the 80s/90s. Most people were happy to rent VHS tapes (read: streaming today) but there were enough connoisseurs, techies and collectors around to keep the premium physical media format of its day alive and kicking.