Well, SCTP gives you messages as first class citizens if you like, or a stream like TCP, multiple channels per connection and many other nice features. It's mo

Well, SCTP gives you messages as first class citizens if you like, or a stream like TCP, multiple channels per connection and many other nice features. It's mostly used inside telco networks. But unusable for consumers. The routers/modems that people have in their homes don't NAT it, many cellular network blocks it, etc. An incompatible overhaul of TCP would face the same issues, unless you implement it on top of UDP.