Especially:
"Obviously, the right solution would be implement a new transport protocol directly on top of IP protocol, one that would provide desired functionality — failure detection and/or multiplexing — directly, without duplicating the features.
And, as a matter of fact, the above was already done. The protocol built directly on top of IP with both heartbeating and multiplexing is called SCTP and is available out of the box in most operating systems.
And here comes the problem: SCTP is not used, even for projects where those features are needed. Instead, they are lousily re-implemented on top of TCP over and over again."
(Not necessarily saying that SCTP would be the best fit for games, more the general point -- that there's room for more than just TCP and UDP on top of IP -- and also that that might not work, due to firewalls and routers refusing to route anything that's not TCP or UDP).