You could say the same thing about many free software projects created for the ecosystem. Many of them could have been created by Apple and shipped as a part of the system. I have donated my precious time to solve problems that should have been solved by Apple before. I’m not extatic about it, but my itch got scratched and hopefully I may have helped other people, too, so I consider it a pragmatic improvement. I can see your point, though, so let’s simply disagree, it’s good for the world to have different people try different approaches.

Yes, and it's a good reason to pause before making new free software for a nonfree system.

Sometimes it is good because it helps people use more free software- but not always. Sometimes it just helps people use the non-free software.

I think the difference is that those weren't created solely for Apple's benefit.

Which projects do you have in mind? Only one that comes to mind for me is Homebrew.