Video conferencing with Jitsi

It's quite possible that I misunderstood why the video bridge helps so much (which it does). It could simply be that the video bridge is a workaround for the Firefox issues mentioned in another comment. The linked hackernews discussion indicates that with peer-to-peer as soon as a Firefox user joins the meeting, performance is degraded for all participants.

It's also likely that you're right and the central server mitigates notoriously limited upload speeds of DSL and mobile (and sadly, where I live, even cable) connections.