Your assertion that it's extremely unlikely that local privilege escalations exist
You misread me. I meant the opposite.
Your argument was based on the premise "assuming there isn't a local privilege escalation attack to which your kernel is vulnerable". I said this premise is invalid (as you just confirmed yourself).
You don't trust your locked front door to protect your valuables, you put them in a safe.
The front door is your firewall. The safe is your host. When someone breaks into your host then it's game over. When you have too much spare time you can attempt to layer further at the host-level but that's usually an exercise in futility.
I can see that we don't fundamentally disagree on many issues. Attempting to protect from all on-host attacks is pointless. Though I don't disagree with you in the majority of what we've discussed, I will always stand up for simple changes to settings that make it just that much harder for unauthorised users to cause trouble. That said those changes must not add too many onerous access requirements for authorised users. Of which, I don't believe asking people to have sudo access to your machine to have super-user access to your database is one.
You misread me. I meant the opposite.
Your argument was based on the premise "assuming there isn't a local privilege escalation attack to which your kernel is vulnerable". I said this premise is invalid (as you just confirmed yourself).
You don't trust your locked front door to protect your valuables, you put them in a safe.
The front door is your firewall. The safe is your host. When someone breaks into your host then it's game over. When you have too much spare time you can attempt to layer further at the host-level but that's usually an exercise in futility.