Yep, WebRTC video with lots of participants is one of the harder cases. But there are other sweets pots.. depending on what information you are routing through your decentralised system. If it's metadata, it's small and much less problematic than having a room of 10 WebRTC video sessions all streaming 10x video streams between each other. But if you are running eg something like a DHT, and then using that to set up transient real time sessions between a few peers, things start to look a lot more manageable.