Most of computer tasks can be done by a small suite of apps:<p>- edit text, view and edit photos, read pdf books, listen to music (all can be done by same application).<p>- edit and view video (could perhaps be done with same program also)<p>- organize files<p>- browse web in a container<p>- perhaps send messages over the net<p>Can't we get something that runs on ARM/x86 that does these basic things and has boot/lockscreen encryption? Why does everything have to be full linux? Something super simple and that boots fast? (I get that an OS has a lot more under the hood, but it could have less under the hood if it was just to carry out basic functions.)
If not linux then what OS do you want this to be on? Building even a very basic OS from scratch for these purposes is not a trivial task. There are also very stripped down Linux distributinos which would match your requriements. In fact, you can install arch linux and just download only these most basic programs and run it minimally.
Doing these 'simple' things requires a massive amount of software behind the scenes. No one wants to take the man-centuries to recreate all of that work
from scratch. Not even Apple did. They built it on top of years of already created work. From a software engineering perspective, you do not want to build something this complicated as a single monolithic program.