That's the $64k question. Who, exactly, is buying rare digital art? It doesn't seem to be traditional collectors, dealers or major institutions. But the same contingent of crypto "whales" speculating in alt-coin assets. A simple bot could even be employed to track auction prices and automate trades. In a sense its not dissimilar to inter-market dealing among art galleries. Without the actual physical objects.
Beeple's Opus
https://www.christies.com/features/Monumental-collage-by-Bee...