I didn't know the PC had a screen size requirement. Don't tell
Toshiba or
Samsung. They use terms like "computer" and "PC" to describe their 10" laptop, er, such-and-such in their marketing material.
Wouldn't there have to be a file system so as to allow delivery of iCloud shared documents or documents synced via iTunes, or do you mean "lack of file system" in the traditional sense we've become acustomed since adopting a GUI? There obviously must be a file system, as I have several apps on my iPhone for accessing stored music files besides the default Music app.
I'm guessing you're like me in that you spend a good deal of time with computers. We take for granted that many people do not or, at the very least, struggle with them.
It is interesting that so many in the forums seem hellbent on considering anything that doesn't meet minute criteria should not be considered a computer. I'm old enough to remember when people used to argue that the GUI wasn't a true computer experience due to the lack of power when compared to working in DOS or within terminal on a *NIX machine. They saw the command line as what constitutes a computer and the proliferation of a computer with a GUI as an affront to everyone and "too simple." The author/blogger Corey Doctorow believes a computer needs to have a user-replaceable battery.
If the computer is going to come to the masses, it needs to evolve. The masses shouldn't need to evolve to come to the computer.