Mobile's came at the cost of composability between programs and the imposition of policy, which are against the Unix Philosophy. I wouldn't make that trade. Mobile's a sad state of affairs, inferior to desktop in many ways.

You can most likely get better security than mobile's, you just need to e.g. learn to write your own SELinux policies, etc. Facilities are there; they just have a learning curve.

How do you write SELinux policies to allow reading only certain files in /proc, where process IDs are not known ahead? I ended up writing my own FUSE-based /proc emulation. The facilities are there, but it feels like writing your own OS.