Matrix is not ready for non-technical people. Way too much stuff to consider as a user. It's similar to PGP a technology that will probably never go mainstream.
Is there? I'm definitely the kind of person who wants to set up my own server and bridges for it at some point, but when I tried Matrix for the first time last week I just created an account at matrix.org, installed a quite polished client and just started chatting.
The iOS client (Element) is garbage unless they fixed it in the last month. I suspect that’s what they’re referring to.
Last time I tried matrix, and mind you that was over 3 years ago. Was with riot.im and trying to use the e2e encryption. The major surprise was not being able to suddenly decrypt older chat messages when OpenBSD changed the User-Agent string for Chromium which as I understand was used to establish the device identity. This is not something non-technical people can or want to diagnose.
It's significantly better now! They've done a lot in the last 3 years, and during that timeframe was when cross signing and e2ee DMs became default. It's not perfect, but it's by far the best I've found for my priorities, and I think it's much more reasonable for regular people now. And if not now, hopefully soon! As a sibling mentioned, some of the alternative clients are also getting good.
I used to believe the same as you about the usability of Matrix, but then I discovered the Fluffy Chat matrix client. It aims and looks to be as simple to use as WhatsApp or Telegram. Check it out if you haven't seen it: https://fluffychat.im/en/