I have an idea: maybe software engineers and tech managers could take a bit longer to do things, so that they don't have to rush to fix them later. Because it's exactly what HTTP/3 sounds: a rushed fix for the HTTP/2 screw up.
Wasn't Google already publishing and promoting QUIC before SPDY got adopted as the basis for HTTP/2? SPDY was more conservative because it didn't replace TCP, QUIC wasn't a fix for SPDY being broken, it was a concurrent and less conservative effort poo.