> OpenBSD maybe gets there eventually.

Nah they won't. The devs have an irrational resistance to the very idea.

I disagree with your analogies. OpenBSD has a focus on auditing to remove all bugs, which is great, but they provide very little to help prevent what can be done if a bug is exploited, and they've certainly had no shortage of serious bugs.

> What use is MAC/RBAC if someone can gain kernel access with a 0 day exploit?

Kernel exploits are pretty rare. Most exploits are in userland.