NFTs are only as valuable as the extent to which the artist has gone to socially validate your purchase of the NFT of their artwork. Which means that it's value is also directly tied to the total social value of the artist themselves. Thus, Beeple.

The NFT market will eventually reach a steady-state no different than the existing art world. But, smaller and more affordable NFT "trading games" (e.g., cryptokitties) might stick around for sometime.