Sure QUIC may be faster, but only as long as you keep getting permission from your TLS CA. Once that stops it's very, very, slow. QUIC is fragile and like other CA TLS things: anything built with it will have a lifetime of only a few years without being updated.
Do we really want to base our web protocol (and other things) on a system that will only allow machines updated in the last $fewyears to participate?
Additionally, the claims of the use rate for the various HTTP versions is flawed in that it is not going per webserver or domain, but instead just counting traffic and of course the megacorp flows it knows about will dominate (they're not checking every webserver). Looking where the light is fallacy.