Do you mean end users, as in the type of people systems like Slack market to, or are you referring to the failures of previous systems that made open specs and

Do you mean end users, as in the type of people systems like Slack market to, or are you referring to the failures of previous systems that made open specs and interoperability a goal? If the former, Matrix the specification and overall system is not what would be sold to the end user. Like you say, most of them don't care how it works or about the philosophical or political reasons why you might choose a system like this. They just want to be able to talk to friends, family, and coworkers and have a good user experience. That's something any company could package and sell in a way that resonated with people, using Matrix as its underlying system. In other words, Super Awesome Chat, Inc. could create a really slick hosted Matrix service and client with great usability, and the end user wouldn't necessarily know or care about how it worked. In mentioning the open specification, it's not for the benefit of that type of user, but at the HN reader who is likely more informed or interested in the details of the technology, the philosophy, or political/sociological implications.