If we wanted to reduce to the absurd, everything is impermanent. There's bit rot, atoms will decay, everything will fade (or perhaps another big-bang).

IMHO, regarding your point on ownership, is what kind of ownership do people want or expect with NFTs.

When I buy a book, a CD, a game or an Amazon movie, I buy it with the expectation to enjoy it for a period of time, I'm not really concerned[0] about lifetime permanence.

If I buy a work of art for millions, I'm probably more worried about permanence, maintenance, security and beign able to pass it down to someone.

NFTs seem to neither here or there in this subject.

[0] What I mean is, I _hope_ the Amazon movie will be available for many years, but I accept the potential loss as not really terrible.