If this were really the case, it would indeed be sad, as the standard HTTP request/response model is both too restrictive and too overengineered for many usecas

If this were really the case, it would indeed be sad, as the standard HTTP request/response model is both too restrictive and too overengineered for many usecases. But both HTTP/2 and QUIC (the "transport layer" of HTTP/3) are so general-purpose that I'm not sure the HTTP part really has a lot of meaning anymore. At least QUIC is relatively openly promoted as an alternative to TCP, with HTTP its primary usecase.