The few who care will make a copy, you can make your own copy or take it from those who do. No DRM is stopping you from taking pictures or make recordings.
Even if ıt was the case that vanishes from the surface of earth, it's not that different from last physical copy getting scratched.
Of course it's different; the path to unavailability describes the society that made it unavailable.
Not at all, CD's also vanish exactly the same way. At some point it is no longer profitable to print those, no longer profitable to keep those in the shelves, no longer profitable to have them in the storage and they vanish.
Those who have them begin using them as frisbees, decoration or simply trash them.
The CDs weren't ripped from active listener's libraries and made unavailable by an uncaring corporation; they deteriorated with time and use.
When I bought that Nirvana CD I bought it for life, and no one has the right to revoke my ability to listen to it.
There is a difference.
Nirvana CDs are trivial to find; hell, if you're looking for virtually any music older than ten years it's going to be on physical media; but most of it isn't digitized.
And the new stuff? Bandcamp is great, and I get to keep the mp3s.