What this website would need is a CDN. There have been projects to build CDNs using WebRTC (which is the technology that WebTorrent uses.) The downside to a P2P CDN is that glowies could track visitors easier, since visitors leak their IPs to other visitors.
Coincidentally, before working on PeerTube, the creator or PeerTube built PeerCDN, which also used WebRTC.
To break it down, PeerTube is an application that uses WebTorrent, and WebTorrent is an application that uses WebRTC. Fundamentally, what has made all of this possible is browsers shipping with WebRTC.