I don't understand why anyone imagines "middleboxes" (there's an overloaded term) won't implement QUIC, drop connections that don't use their CA cert, and then fuck with the connection by mitm. ISPs might not in the west, but they sure as fuck will in less liberal societies, and every corporate network will eventually.

The entire point of "middleboxes" is to solve a problem on a network you control. The problem doesn't go away "because encryption". They're just going to find another way to do what they want, because the protocol gods refuse to add needed features. Whoever decided that this was going to solve the problem didn't spend more than 5 minutes thinking about it. It's actually creating more problems.