I don't know what differentiated Zoom from its competitors, but a self-administered server will always be harder than using SaaS for stuff like video calls / WebRTC.
WebEx seems to work fine too for huge calls, although I use the native client for it.
At a previous job, I once helped a tiny bit with setting up and configuring the company's Jitsi instance (wasn't the admin though).
As far as I can tell, the differences mainly affect non-P2P mode, which the server will enable above some bandwidth or participant number threshold.
Another thing all these WebRTC clients have to achieve reliably is dealing with different NAT setups and firewalls (one piece of this seems to be achieved with technologies STUN and TURN).
I guess video conferencing is at least as complex as implementing real-time multiplayer games over the internet.
Edit: Just read up that WebEx predates WebRTC and uses it only for interop with other tools. Zoom uses a custom technology stack as well as far as I know (I have no idea if it involves WebRTC).
So maybe WebRTC really is hard to scale up large numbers of participants.
Haven't heard much good about Teams in this regard either (which uses WebRTC AFAIK)
Zoom does use a custom protocol. This is why it doesn’t work nearly as well when you take a call in the browser client. Not because WebRTC isn’t up to the task, but because Zoom hasn’t invested in it.
Ignoring costs, while having someone host infra for you will always be easier than managing it yourself, I think we’ve really improved the DX of hosting your own WebRTC infra with LiveKit: https://github.com/livekit/livekit
WebEx seems to work fine too for huge calls, although I use the native client for it.
At a previous job, I once helped a tiny bit with setting up and configuring the company's Jitsi instance (wasn't the admin though).
As far as I can tell, the differences mainly affect non-P2P mode, which the server will enable above some bandwidth or participant number threshold.
Another thing all these WebRTC clients have to achieve reliably is dealing with different NAT setups and firewalls (one piece of this seems to be achieved with technologies STUN and TURN).
I guess video conferencing is at least as complex as implementing real-time multiplayer games over the internet.
Edit: Just read up that WebEx predates WebRTC and uses it only for interop with other tools. Zoom uses a custom technology stack as well as far as I know (I have no idea if it involves WebRTC).
So maybe WebRTC really is hard to scale up large numbers of participants.
Haven't heard much good about Teams in this regard either (which uses WebRTC AFAIK)