I was thinking more about it being open and interoperable. It will be functional, but as you point out, the actual ecosystem will be mostly proprietary to Apple and a few other big companies. And at that point it does not really matter (lol) what it is called, it is just another random proprietary protocol.
Matter itself is too low level, they will just make higher levels proprietary and require certification to operate on their network, so true third-party devices would be locked out, rendering the whole thing useless, unless you are already sold on all Apple stuff. I personally would not build my home automation around this, it is jsust asking to be extorted in the future.