That idea is wrong, though. These same people thinking harnesses are part of a moat are also boasting that s/ware is easily writable now.
There's no secret sauce in a harness that you can't vibe-code into your own harness.
Except you'd need the knowledge of what to vibe-code, no?
What knowledge? If you've used a harness, you know what it is supposed to do for you!
What further knowledge do you need that can't be extracted from an existing harness?
I'm not saying you're wrong necessarily, but I do think that when the actions and words of a company conflict, it's a pretty safe bet that the words are just posturing and the actions better reflect their actual belief. In this case, regardless of what they're saying about software being easily writable now, they clearly seem to at least think there's something valuable in the harness if they're not open sourcing it.