To be clear, I'm not installing those things either. Everybody has WhatsApp, so that's my fallback, it's a common denominator. Signal is superior, so that's my preference. For personal conversations, I don't use anything else.
Then for work, I have to use the tools we get (be it Slack or Discord or Teams). And when a community is on Slack or Discord or IRC or discourse or whatever they use, well I have to go there to talk to them.
> My employer uses Microsoft 365 where all our data is on Microsoft servers
Yes I agree, that's a problem. Slack, Discord, same thing everywhere. Companies should self-host e.g. a matrix server, or at least use a provider from their own country. But I believe that self-hosted Matrix would be better than Slack for companies.
> I don't agree, [Matrix] is superior for me.
Out of curiosity, why not Telegram then, if you don't care about privacy and encryption?
> if they grow the "normies" will rapidly outgrow the evangelists who would be inclined to donate
They currently have 70M active users. Those are not evangelists.
> If the main matrix instances enshittify, I'll just run my own
Which is more complicated for approximately everybody than "if Signal enshittify, I'll move back to WhatsApp or to the next alternative to Signal".
Matrix brings its lot of issues. For instance, startups obviously wouldn't care, but corporations would never accept "any Matrix client" to connect. So they would somehow want to make sure that their employees use approved clients. I don't think this is currently a thing in Matrix. But even if it was, it means that corporations wouldn't benefit from "I can use any client I want", and chances are that they would self-host and not federate. Better than giving their data to third-parties, but still not the dream of federation or freedom.
For personal use? Normies use the main Matrix server, it's not really federated. And Matrix servers collect a lot of metadata. Wasn't there also security issues, where a Matrix server could inject ghost users into rooms?
All that to say, Matrix does not solve the problems that Signal solves. Matrix solves other problems (well, mostly "I want to self-host a chat and I want something cooler than IRC"), but then it makes sense that Matrix is not a replacement for Signal and Signal is not a replacement for those Matrix use-cases.
Bridging is a weird hack. I have only been confronted to Matrix bridges to IRC channels, and it was making everything worse for IRC users (essentially forcing the IRC users to either move to Matrix or ban the bridges).
