Matrix and Signal have very different objectives. Matrix wants to be an encrypted IRC or Slack. Signal wants to be a secure messenger you can entrust your life to. They are both worthy projects; there's not as much overlap as people think.
I would probably characterize Signal as "most possible safety for the average nontechnical user" which entails trade-offs against absolute safety for certain UX affordances (and project governance structures that allow for these decisions to be made), because if said affordances are not given, the average nontechnical user either simply won't use Signal or will accidentally end up making themselves even less secure.
If nothing else it’s an incredible foot in the door for a lot of people to make the leap to something like jellyfin later.
This "average nontechnical user" stuff, though, miss me with. For 2 decades people have been encouraging the "average nontechnical user" to do incredibly unsafe things on the premise that any kind of message encryption is the best alternative to sending plaintext messages. No: telling people not to send those kinds of messages at all, unless you're dead certain the channel they're using is safe, is the only responsible recommendation.
I want there to be something like Matrix that is designed first and foremost as a large-group realtime chat program (really, as a meaningful FOSS alternative to Discord), and it should make different tradeoffs than Signal. I'm actually willing to entirely forego encryption, at least at first, to make this happen - IRC wasn't encrypted and Discord isn't either, and these are things I want to replace with something better. Matrix's UX is still noticeably worse than Discord's, and I'm skeptical that the ostensible security gains from the encryption are worth it, especially given the problems with device verification UX, metadata leakage, and the fact that as the number of people in a group chat grows the possibility that they will take a screenshot of the encrypted message sent to them and leak it to the press grows higher and higher.
Eh. You misunderstand me. I don't really have too much of a view on this personally. Unless you specifically think that the term "average nontechnical user" is a bad term.
N.B. for other readers of this thread to flesh out my initial point:
Signal specifically didn't do that recommendation until they got sufficient critical mass of users in 2022. In particular Signal gracefully degraded to unencrypted SMS if the other side didn't have Signal.
Likewise Signal required phone numbers until 2024 when it shifted over to usernames, with all the security vulnerabilities that entails.
Signal has repeatedly made trade-offs that prioritize UX over absolute security even in 1-1 chat settings. That's not to criticize those trade-offs, there's a variety of reasons why they make sense or don't. But Signal has consistently demonstrated that it is not willing to make severe compromises to the UX and understandability in the name of absolute security and that it will balance the two.
Also to your point
> For 2 decades people have been encouraging the "average nontechnical user" to do incredibly unsafe things on the premise
Sure I can agree with that. But that wasn't my point either? Unless again you specifically object to the term "average nontechnical user."
To go maybe too literal: when I'm working on machines that could physically eat me, I don't trust myself with just one off switch -- I want redundancy. And since computers are horrible piles of ridiculous complexity, the closest I can get (and not really get close) is trusting some of the top minds to overthink the crap out of it in a way that I can't do with the systems I manage.
But again, YMMV.
That said, the uptime is still probably worse than Signal. I didn’t mean trust the reliability. I meant the security.
matrix's users want it to be a decentralized/encrypted irc/slack, but unfortunately matrix's maintainers believe their mandate is to build a next-gen tcp/ip (or something very close to that)
which dooms the project
unsure what makes you think we want to build a next-gen tcp/ip, but can I have some?