Why is fully decentralized option like WebRTC not considered ?, there is no real need for message apps to be centralized especially on mobile. Loss of message

Why is fully decentralized option like WebRTC not considered ?, there is no real need for message apps to be centralized especially on mobile. Loss of message queuing can be mitigated easily when both end points are more or less always running and messages sent only when both parties are on online. TURN relays could still be a problem and potential censorship blocks. However the protocol is standard it is not very difficult to setup one even behind NAT. You could even bundle lightweight version with app and make all the clients relays too making it very hard to crackdown on