likely because they know no one would pay for it. YouTube would die overnight(in terms of content creation). The only people remaining would be the people like Markiplier or the huge content creators that made it big way early on, and even then, I think you would expect heavy resistance against the big content creators just because they’re gonna be the ones that are fronting the majority of the bill just due to how many videos they have uploaded.

YouTube would have better chance of survival requiring a subscription to watch the platform than if they were to try to get content creators to pay for storage, it would be content source suicide.