> Maybe we need some kind of protocol that can spread the load where popular messages are duplicated across the network instead of being stuck on one node that can get overwhelmed.

You mean like any proper P2P protocol?

Add to this multi-cast on internet level, and everybody could actually operate something like YouTube on their internet router…

But of course economic interests of some (already ultra rich) minority will prevent that forever, even we could have it just right now form the technical standpoint.