However, all the areas where Linux has these strongholds are [very] technical. Especially in the wake of this "consumerization of IT" phenomenon that rides on a big wave of money, it has become of paramount importance to have an OS excelling in ease of use, fantastic user interfaces and overall smooth interaction with the average human being. Linux and free software in general has always been utter shit in these aspects. Everybody keeps asking why and I think everybody actually knows the root of the problem.
I'll illustrate it using an analogy with a work of art, something like a painting, a song, a poem or even some kind of complex and yet elegant mechanism. When true artists present such creations to the world, the world has no saying like "I don't like the 3rd verse, change it!" or "Maybe you should've used some yellow here! Redo it!". This is not how true works of art exist. The author assumes a certain position, creates something as a whole and then the world judges it as being overall good, great, crap, etc.
I think the same principle applies to human interaction layers in software. Great user interfaces are works of art. Their creators need to conceive something that is at the same time useful and yet it enchants your senses every time you use it. It must feel cohesive and yet it must handle all sorts of tasks that are not strongly related to each other. Worst of all, a great user interface for an OS needs to be tightly integrated with the code doing the heavy duty lifting in the background. Their creators need to assume a position on how various things are done and their creation should be judged as a whole.
Why are state of the art user interfaces missing from Linux? Because most creators of great works of art live their lives in the shadow of powerful sponsors that often profit greatly from financing the creator through their "wonder" years. There are no such sponsors in the Linux world. Every single developer of Linux software creates his own user interface as well as he can. The end result is like a giant wall of hand paintings made by 5 year olds. Cute, but clearly nowhere near work of art status.
This situation will not change until the open source / free software movements will figure out a way to finance artists and strongly integrate them with developers. It seems to me like an impossible task that can only occur in a classical style software company like Microsoft, Apple, etc. So I think Linux is doomed for a long time to run in the background, doing the heavy lifting on space stations, labs, devices and servers. Occasionally it will spawn a child that apparently is not retarded, like Android, but take a second look and you'll spot the root problems in no time.