It feels as if Automattic doesn't do a complete paradigm shift and become truly open with their software everyone is going to give up on them entirely - at least everyone with significant talent and investment.
I agree with you that Automattic needs a paradigm shift (massive leadership change, probably), but I don’t think the openness of their software is the problem.
Automattic has other issues (leadership, especially!!) but software development happens largely in the open. Just look at the GH issues and PRs in the WP-calypso and Gutenberg repositories, and you’ll see even a lot of technical discussion and planning happening completely public. You can even chime in if you want :)
Automattic has lots of issues. But they simply have much more open software development practices than nearly any other tech company (most of which are completely private and closed source). I just don’t think this is the core problem.