You also get limits on how many VMs your machine can run, each VM needs gobs of storage and locked-out RAM blocks, and sharing directories between the host and guest, compared to bind mounts, is something that makes me remember for my root canal dental jobs wistfully.
I can see how you'd need a crap ton of disk for MacOS virtualization, but again, why do you need it?
If it's isolation for builds, fix your build. If it's isolation for tests, live with it. If it's for running your app, write your app to properly run in the app sandbox.
But still not "as fast as it gets". And I want it to be as fast as it gets.
My point is "as fast as it gets" is using MacOS how MacOS is designed: ie, through sandboxing and not containerization that pretends the MacOS userspace is Linux. It's not Linux.
There is a fundamental trade off between isolation and performance. You cannot securely share resources without overhead.
Isolation fixes the problem for free and is more similar to how I build for Linux. Why would I want another solution?
Further you can sandbox processes just fine on MacOS without needing to mock the whole userspace, like you do on Linux. This will give you the same degree of isolation that a container does.
I get the point of isolation for build/test situations. But Apple provides a neat virtualization framework, and you get security + isolation + reproducibility + decent performance.
It seems like if you feel the need to containerize the userspace on MacOS you're using MacOS wrong. It's not the same thing as the Linux userspace, and doesn't have the same kernel features that would let you do so cleanly or performantly.
Orbstack is moving mountains to provide Linux-native perf and support for containers and it still makes me beg the question: why are devs allergic to just using Linux natively? At least I understand why Orbstack is useful, I don't know why containerizing MacOS itself is.