You're probably right that it's the UX of the OG Element that was the original problem people got hung up on but Element X isn't actually a relevant answer until it's usable, regardless of how much better it sounds like it will be on paper. A secondary problem people got hung up on was the endless parade of "you're just using the wrong client, try ${this}" and then finding it was missing half the things that they were told Matrix can do.

I'm still optimistic about Matrix but I am a bit worried that it has lost a lot of steam because of this UX history.