At first glance I don't think it's fair to say "ENet did this a decade ago". ENet simply provides multi channel communication over a UDP stream. It doesnot provide 0/1 RTT handshakes, encryption of the protocol beyond the initial handshake, or HTTP bindings. Based on some Github issues it doesn't even look like there was a protocol extension/version negotiation.

QUIC is also decently old itself, the last 7 years have been spent proving it is well suited for the real world and able to be iterated upon. This is the kind of difference that matters for standards track vs ignored.

nitrix isn't referring to the other features, simply the concept of reliability over UDP to minimize overhead. The games industry has been using this concept for decades for efficient networking, and only now is the web community thinking about it.

Your comment made me wonder: Is the PR to add ipv6 support to ENet still open? Last times I checked was maybe 3 years ago. Seems it's still open: https://github.com/lsalzman/enet/pull/21