There is no such thing as computer security, in general, at this point in history.
Indeed. Why lock your car door as anyone can unlock and steal it by learning lock-picking?
That subtlety is important because it explains how the backdoors have snuck in — most people feel safe because they are not targeted, so there's no hue and cry.
Are they wrong? Do gradations of vulnerability exist? Is there only one threat model, “you’re already screwed and nothing matters”?
It's still worth solving one of these problems.
The problem in both cases is the massive attack surface at every level of the system. Most of these proposals about "security" are just rearranging deckchairs on the Titanic.
If you can't keep a nation state out (and you're referring to your own state, right?) then you can't keep a lone wolf hacker out either, because in either case that's who's doing the work.