[murraypaul]

There's no particular hardware reason a device can't have both. The problem is that there is no good UI for it.

Hmm, that sounds like what I've been saying

One of the core Android principles is that you never need a file manager. Ever. We wanted to avoid the obnoxious "sneeze and a file picker appears" syndrome of basically every other OS.

Well, every other OS with one glaring exception.
They are choosing the follow the iOS example, so they must think there is some sense there.

Or, as Steve Jobs put it:

in every user interface study we’ve ever done […], [we found] it’s pretty easy to learn how to use these things ‘til you hit the file system and then the learning curve goes vertical. So you ask yourself, why is the file system the face of the OS? Wouldn’t it be better if there was a better way to find stuff?
Now, e-mail, there’s always been a better way to find stuff. You don’t keep your e-mail on your file system, right? The app manages it. And that was the breakthrough, as an example, in iTunes. You don’t keep your music in the file system, that would be crazy. You keep it in this app that knows about music and knows how to find things in lots of different ways. Same with photos: we’ve got an app that knows all about photos. And these apps manage their own file storage. […]
And eventually, the file system management is just gonna be an app for pros and consumers aren’t gonna need to use it.

Imitation is the sincerest form of flattery.