Well, YT is literally getting petabytes uploaded to it. Every single day. Thats 1000 terabytes, and thats 1000000 gigabytes.
I bet you haven’t even seen a petabyte of storage in one place (assuming you didn’t go to a data center yourself). How is a small company, or even fediverse, gonna handle that? Thats absolutely insane amount of data and, without moderation or curation, it is not feasible.
It’s a giant waste of space and resources, to be honest. Most videos are seen once, and the rest is mostly spam or bad quality content.