When I have a full team of people with 1080p webcams and a solid connection I can notice the quality. Most of the time not everyone fulfills those requirements and the orchestrator system has to make do
I mean you can easily create your own fully meshed P2P group video chat in your browser just using a little bit of JS that would support everyone running 4k, but it will fail the moment you get more than 3-8 people as each persons video stream is eating 25mbps for every side of a peer connection (or 2x per edge in the graph.)
A huge part of group video chat is still "hacks" like downsampling non-speaking participants so the bandwidth doesn't kill the connection.
As we get fatter pipes and faster GPUs streaming will become better.
edit: I mean... I could see a future where realtime video feeds never get super high resolution and everything effectively becomes a relatively seemless AI recreation where only facial movement data is transmitted similar to how game engines work now.
4k for videoconferencing is nuts. The new camera should be an improvement over the old. Plus, being able to show your actual, physical desktop can be Andy too. Using your iPhone as the webcam will still probably give you the best quality especially if you are in a lower light situation.