> If I were the Internet Dictator, I'd be a big fan of standardizing the semantics of http separate from the physical transport and then defining best practices for using alternative transports in the wild, and then eventually standardizing what comes out of that process.

This is what the IETF has been doing for several years already as part of the core HTTP specification rewrite. Namely, see the HTTP Semantics document https://www.ietf.org/archive/id/draft-ietf-httpbis-semantics...

Semantics are common, how those map to specific transport - how it looks on the wire - is then the job of each individual HTTP version.

It reads like you're overlooking the act of standardization in improving the definition of a protocol. Experimentation is good but often only focuses on a limited set of use cases, deployments, or implementations. Standardization is great for interoperability across a more diverse set of all those three. This typically yields protocols that are more generally applicable for a wider population of the Internet.

Google QUIC was focused on an HTTP use case and thatbran through the entire design. Through the IETF process, the design evolved to be a far more generic transport with rich extensibility and modularity.