PeerTube can serve a video to thousands without a big server. The thread explained why that still isn't YouTube (github.com)
It's a free, federated video platform from the French nonprofit Framasoft: no ads, ActivityPub federation with the Fediverse, and peer-to-peer playout so simultaneous viewers offload bandwidth from the host.
A working YouTuber did the money math and it was brutal — a ~100K-subscriber channel that couldn't survive on under $500–$1,000 a video, which PeerTube has no way to provide. As one authority put it: the tech does exactly one of the four jobs a YouTube replacement needs, and it does that one fine.