Why are those over specialised operating systems for small computers needed?
Is it because of how light they are? They still use the essential free programs and libraries, that are part of your average GNU system. Isn't it technically feasible to install a GNU system on a device with such hardware capabilities, but with a lighter desktop environment more suitable for touch screens and small keyboards?
I've used Android on another person's computers (I would not use such system on my computer). The system seems badly designed and written. Even simple things, like writing and saving a plain text file seems very inconvenient.
For example, with the default text editor, it's hard to highlight text, you can't change the font to a monospaced one, you can easily loose your progress because of a single simple misclick (happens constantly), can't change the encoding or EOL style and can't choose a place where to save the file. Also, it isn't obvious where files are even saved, so you can easily copy them, archive them, upload them or make a backup. These are very basic things, that even the most simple of text editors on GNU can do. Even Notepad can do those.
This is just a single example, but the whole system feels like this. Practically everything feels very awkward. Things like switching between opened applications:
You first minimise the current application, then open another application from it's shortcut for which you must browse trough all running and not running applications. It's hard to see which applications are running. You can't even run several instances of a single application. If you want to edit several text files, you must use the awkward interface specific to the editor, if it has such interface.
As I understand, even simple things like connecting a USB keyboard are needlessly complicated.
I know how to use GNU. I don't want to learn the specifics of another system, which is obviously inferior in most aspects. GNU has a huge library of well written, well designed, well tested, stable and convenient free applications. And most importantly, the whole system is already free as in freedom.
