If they were to support darwin containers, what would be the point? Literally nobody would build to it, Linux won.
because nobody does ci/cd against macOS or iOS apps right?
There aren’t any app developers avoiding the Apple ecosystem because there aren’t Darwin containers. They don’t sell server hardware and by all accounts have no intention of ever reentering that space. So they’d spend a bunch of developer cycles to reduce their own revenue stream with no apparent upside beyond “goodwill” which they’ve never been overly concerned about.
If they're investing resources into it regardless, they might at least try making something that Docker for macOS and co. haven't solved the same exact way already. Something that, due to their almost unhealthy obsession with "system integrity", only they can realistically make. Like native containers.