Im regards to webRTC: vp8 supports temporal layers, h264 does not. Meaning you can encode and upload 1 stream while participants with different network conditions can be served the best possible framerate. Vp9 and av1 also support spatial layers, which is the same for the resolution. For this you currently need simulcast in vp8 or h264.
Yeah, it is like people care about this when they literally can't hear a person on the other side because of fans. Without hardware support all this codecs are useless on mobile.
If you will take a look at Zoom, they are essentially doing simulcast over websockets/webrtc data channel and it works well for large amount of participants. Unlike VP8 that can't handle even two.
