You are correct.
Nearly all youtube channels can be fully served off a single laptop. 260 concurrent streams at 1080p 3mbps is achievable over gigabit ethernet. Very few channels exceed this for any appreciable amount of time. And in those cases we can leverage a very small amount of the client's ressources to further propagate the stream. This can be done with repurposed bittorrent dht.
Now all we need is federated RSS and a locally running content curation algorithm and a social review system (like buttons and reputation history)