But then the solution becomes: stop using computers, because the kind of sophistication required is out of reach for a very large part of the population. So, computers will stay part of everyday life. Making the interface simple and predictable, and locking features that can be abused may be fighting the symptom, but it's better than nothing.
Well yeah, I agree but even in the most locked down system people will still (involuntarily) find ways to get screwed or otherwise not be able to discern what's good and what's bad for them.
It sounds a bit nuts and I'm being slightly hyperbolic on purpose but I think the way to go is to slow digitalization in the public (i.e. our everyday lives) down a bit and properly educate at least decision makers, children (or young adults) and teachers about how this sorta stuff really works and how their rights are being undermined in the digital world.
Alas, the pandemic has been a big blow to that as well.
I don't think this is a guarantee. Already most people's primary computing device is their phone; there are households where everyone has a phone and a couple iPads and no PC; and iPads or Android tablets seem to be fairly common as POS terminals and kiosk devices.
PCs will definitely always be around for serious content creation and heavy work; but the group "very large part of the population" is also the group that is less and less likely to own a PC or use one other than at work or for school.
Tablets and phones are computers, IMO. They're still general purpose machines. For many tasks, their interfaces are less confusing than a desktop's interface, which is progress, but when it comes to web apps, there's no difference, and especially phones can be really clumsy.
Not using computers would be falling back to paper forms and mail.
First macOS, then iOS, and then Android, have made some inroads. My mother is very clumsy around computers, but a iPad she can manage. It's not perfect, but much better than 10 or 20 years ago.