> Unfortunately implementing an Apple style architecture on Linux would be very difficult.

On desktop Linux as we know it, yes, but Android manages it alright, mostly via SELinux+seccomp.

Android is basically a different OS that happens to reuse parts of the Linux kernel.

Yes, it reuses all the security features.

It respins UNIX security in favour of a mix of SELinux and a (mis-)use of UNIX user/group identities to contain apps instead of users. Linux distros sort of do that too but only for system services, whereas Android does it for user visible apps.

Doesn't each app run as it's own user? The OG of security features.