https://blog.torproject.org/sunsetting-tor-messenger
"We, the people" is such a fragile concept when it comes to resource stability (time, money, dedication). Looking at a project like Linux, there are commercial interests that fund a large part of the pipeline.
Running the actual network and developing the various messenger clients add a layer of organizational complexity that, in my perspective, only private companies have been able to honor, and only to the extent described by the OP.
One could settle for less Service, but then we have XMPP with various encryption schemes. Too complex to set up.
The ideal would require no servers, because the chat would be fully peer to peer. People wanting to be anonymous could just connect through Tor. (Each user account is just a private key, etc, etc.)
Of course, in reality everything is behind a NAT and/or firewall. It wouldn't be too difficult to have "dumb" servers that just exist to pass messages hosted by the community though.
It takes a few maintainers per platform and a few people willing to lead the effort, but I think we could get enough people on Hacker News to help out.
(I've actually been debating making an "Ask HN: Would you join this effort?" post but have been putting it off for one reason or another.)