My examples for the home-grown tools were things like their deployment tooling which is far less well developed than other tools in the ecosystem. However I can see Omarchy going the same way.

It's very easy to quickly build something that solves 80% of your problem, and because it's tailored for what you need and you understand it, it's easy to believe that's better than the existing tools. The problem comes in the long term, in supporting more use-cases. You can decide not to support more, but that's a sacrifice (and in the case of Omarchy the end users may bear the brunt of that), or you need to put the time in to develop it.

Omarchy will have less development effort than macOS, their deployment system will have less development than Docker/Terraform/etc, and that's all a trade-off.