You have it the wrong way around. People who cordon themselves off and only leave HTTP working aren't on the Internet.
They don't want non-web apps to work. Those networks deliberately rule out networked games, uTP, VoIP, IPsec, WebRTC, etc.
If you want to worry about people teetering on the edge of the Internet, you should worry about people behind NAT and its prevalence to the point of people confusing NAT boxes and routers...
(Re your last sentence, it's not a UDP replacement, see other comments.)
They don't want non-web apps to work. Those networks deliberately rule out networked games, uTP, VoIP, IPsec, WebRTC, etc.
If you want to worry about people teetering on the edge of the Internet, you should worry about people behind NAT and its prevalence to the point of people confusing NAT boxes and routers...
(Re your last sentence, it's not a UDP replacement, see other comments.)