And that's exactly one of the reasons (though not the only one to be sure) Android and other tablet OSes is mostly a toy when it comes to productivity applications.
I don't use "loads of people" argument. I use "loads of people found it useful" argument. Though this argument will probably fall on deaf ears, try to consider why different operating system came to the same hierarchical storage method - historically there is nothing linking FS implementation in DOS, UNIX and Mac OS classic yet they all have arrived to the "file system" idea. So maybe, just maybe, it's not an implementation detail, what's with all those systems implementing it without sharing a single line of source code.