The real problem of these is the existence of the validating infrastructure for NFTs. If you have a physical collectible, you are completely independent of anything except for a market and expertise. With NFTs, you count on, for instance, Ethereum being operating and (at the least the variant the NFT is issued on) accessible. And, possibly, legal.

Owning physicals is much simpler. Infrastructure and expertise in provenance of practically any collectible at this point is extremely reliable. And, most importantly, will be guaranteed to be invariant and exist in perpetuity.

How long it will be before NFT's go away? Hard to say. They may persist for a long time. After all, there has never been a decrease in the growth of suckerdom. There is something painfully Darwinian in the growing numbers and rush of people to these kinds of get-rich-quick schemes. Either this is just winnowing or a preface to a wholesale collapse/correction.