I mean fundamentally the goals of WebRTC and game engines just aren't that well aligned. All games are going to want an authoritative server to hold the master state and reconcile clients. Where as WebRTC is very much interesting in P2P. All the STUN, TURN and ICE stuff is pretty much wasted on a game server.
The spec is also way over complicated, heck it covers DTMF for crying out loud.
Having experimented a bit with WebRTC myself, I agree that it is overly complex but it also offers many features. And if usage is too complicated for game developers, they can still libraries that simplify the usage for their purpose.
And while WebRTC is complex, you can ignore almost all of that if you're just doing client to server data channels. You just need to speak ICE lite, DTLS, and SCTP, all of which have libraries. See some of my comments from months ago for more details.
I think your proving my point here. That's a lot more to ask than a simple libsodium based crypto + auth token that something like Netcode.io uses.