Yeah but you can just continue to use HTTP/1.1, which is simpler and works in more scenarios anyway (e.g. doesn't require TLS for browsers to accept it).
Without HTTP/1.1 either the modern web would not have happened, or we would have 100% IPv6 adapation by now. The Host header was such a small but extremely impactful change. I believe that without HTTP/3, nothing much would change for the majority of users.
