Understandable actually. Server maintenance costs money and if a 3rd party chat app; which significantly has more usage than other forms of social media; is trying to connect to the server, they have to handle that traffic too. Remember, it is not just about data size, but also the sheer volume of connection to handle.
I think the solution is just P2P with each peer acting as a relay to the other too. The protocol needs to be designed in such a way that no-one in the middle can reply to send false acknowledgement so as to prevent sybil attack or other attack where a malicious actor is a part of the network.