> Peer to Peer for streaming doesn't seem a reasonable alternative at any scale, since most people own phones and then laptops, and much fewer desktops.
Peer to peer streaming of the PeerTube type seems to work reasonably well. Unlike Mastodon, etc., you don't have to sign up to receive content. You just click on a URL and it works. What it doesn't offer is discovery. Nobody will find your stuff on PeerTube. They might follow links there.
I put metaverse tech demos on PeerTube.[1] Works fine, few views. No ads.