I always have the feeling that WebRTC had so much more potential than has been realized. I wonder how things might have turned out differently if it had better server and browser support ~5 years ago. I remember trying to use it for a game at the time and had trouble finding a good server implementation, and had all sorts of issues with Safari.
In the near future I'm not sure there will be much reason to use it over WebTransport, unless you're doing p2p. I actually prefer WebRTC's data channel API, since you can get separate datagram streams, whereas with WebTransport you have to multiplex them yourself[1].
[0]: https://github.com/anderspitman/awesome-tunneling
[1]: https://datatracker.ietf.org/doc/html/rfc9221#name-multiplex...