The same reason why owning a business is less of a commodity than electricity.

It's the ultimate monopoly. Anyone with more compute will ultimately be able to out perform any business you could invent ultimately locking you out of competition.

The owners of compute will make a killing and can set whatever price they like. But if the owner is someone like say amazon, then what actually stops them from using their massive compute army they already own to enter the most lucrative businesses for compute slowly dominating everything?