I guess the way to achieve LiveStreaming is to encrypt and to send data from one device, and the others shall receive and decrypt it. For P2P, video calls require “all in one” instead: encrypting, sending <-> receiving, decrypting.
While I think it could be possible for all-time powered devices, e.g. PC systems, it would not be suitable for charged handheld devices now: First, a device driven by a high-end SoC with enough memory to do the tremendous work fast and efficiently is absolutely necessary, still giving other apps enough “air to breathe” and to work acceptable with short UI/UX response times. And second, low power consumption (or a huge battery). Performing such video calls will discharge a battery within a couple of hours using todays high-end technology.
Please do not get me wrong, I would love to see this technology succeed on any device, even for P2P video chats, but the time has not come, yet. For now, a (one way) LiveStreaming solution seems to be a more realistic goal to achieve.