I've noticed that if something is possible, your children or grandmother with do it, somehow. I hand out Chromebooks to relatives because of the low support requirements, and yet STILL every time I get one of those things back there are dozens of outright dangerous extensions installed. These are folks who know how to click on the icon for their email and that's it, and yet the garbage finds a way in. It's like trying to seal your basement against water in the everglades.
I agree, and I believe this is in part because it is these kind of people that malware is targeted at. We, the tech savvy, will be smart enough to not do something because we pay attention at permissions or what extensions, programs, tools, etc are doing or want to do. The tech illiterate still do know how to use Google, search for what they want to do, click on the first thing that looks like it will do what they want, download and use it. If it doesn't do what they want, it remains there and they go and repeat these steps until they find exactly what program, etc does what they want, all while the bad ones remain installed, doing bad things.
My wife fell into this category when we first met, after I began teaching her even just some basics and she learned to question things and be more careful, I haven't needed to "diagnose" her computer in a long time (I still do regular maintenance, but irregular issues never come up anymore). So I would say that education is the biggest key in this regard, teach them to start with a zero trust model.
Tech savvyness and paying attention will not save you when you're bombarded with dark patterns all the time. Even then, I prefer not to be one click away from losing my privacy, money or being bombarded with ads.
If I am understanding you correctly, dark patterns are meant to be a psychological hit to you, it's not tech savvyness but clarity of mind and knowing that most every big business out there wants to make money off you and will do anything to get that money. This is a huge reason I am not on Facebook (among others, including the standard ones), and other social media platforms. I investigate claims myself, and do not trust what is thrown at me. Perhaps this is the biggest reason dark patterns have never worked on me. Also keeping a strong privacy/security setup that you don't compromise on helps too.
It's totally possible to have both: on first init, have the user choose whether they want to prevent installing apps from 3rd party stores. Changing this setting requires performing a factory reset.
Problem solved. If you want the walled garden, opt in at the beginning, and now your children/grandmother are safe as long as they don't literally reset their phone, wiping all their pictures/apps/whatever.
