That just isn't borne out by the data. QUIC builds upon the learnings of SPDY and encrypts and protects a bunch of control structure to make it impossible for middleboxes to tamper with connections (e.g. forging client disconnect packets) [1]. 75% of Facebook traffic runs QUIC which indicates that middleboxes are largely not blocking QUIC.

> Companies don’t put these things inline for fun, they do it because they want to block traffic. Allowing bypassing it breaks their policy

Right. And QUIC is a technical response to say "no - you have to control the actual endpoint to enforce the policy, you can only control endpoint access to your network but you have to be a common carrier once you allow that access". A telephone equivalent would be the telephone company discontinued your call because they didn't like what you were saying to the other person on the end of the line (& this is ignoring the fact that QUIC also improves request errors, tail latency and other quantifiable metrics by excluding the kinds of actions that carriers can take on that traffic).

[1] https://docs.google.com/document/d/1RNHkx_VvKWyWg6Lr8SZ-saqs...

[2] https://engineering.fb.com/2020/10/21/networking-traffic/how...