Say you buy a JPEG of an artwork. This is equivalent to a print which can be reproduced indefinitely.
The NFT is essentially just the artists signature on a print. It’s literally the artist signing a hash of the content.
The storage location of the content isn’t important. It’s really just part of the history of the artwork.
The owner only needs to keep a copy for their own collection, and can put it online themselves if they like.
The NFT will verify that the owner bought a signed copy from the artist regardless of where the JPEG is actually stored at the time.
I’m not commenting on how we should value this - just that the storage location going away doesn’t seem to be a showstopper.