Seems like you think the whole collection has to be in one single torrent, rather than a separate torrent for each video, and that the complete works of all channels have to be seeded from a single source?
The Pirate Bay existed… huh, still exists, OK… without requiring any single person to have all the pirated content on any single system — the combined size of all videos on YouTube may be 10 to 15 exabytes or whatever, but no single video, no single creator, is close to that. Even LTT is about 3.6 petabytes for their entire working-archive backup system last I heard, and if they wanted to stream those as a torrent, well, the files are right there.
It may not suit the current way YouTube content is consumed, where you share a link to a specific timestamp and whoever follows that link can see that moment almost immediately, but that doesn't detract from "can people share videos, perhaps even ones they made themselves, using this system?"