I live in france, and here, youtube is barely usable anymore, because everybody uses it. Streaming sucks, because video on demand is the worst pitfall of the internet architecture.
Websites are great for static pages. It's also great to advertise things, because html is easy, and quickly doable. But for other things, I don't believe it's really worth it. I dare you to find a html5, lightweight internet browser that can do optimized javascript, for what, checking your gmail, and connect to the facebook server farm? Why not using a mail application instead ? And then come up with SPDY, which is not so fast anyway.
Not everybody wants websites. People also like to share files, do video conferences, which are not possible with a centralized network, or really painful and expensive. Think about skype and bittorrent.
Those are economic alternatives because access network are not only expensive, they're not technologically viable.
Saying p2p is not viable because it is slow is a joke, because the way we use the network to make websites is already slow and require tremendous amounts of bandwidth. You're comparing airplanes and bicycles.