We think it’s simply that Microsoft made the mistake of trying to reinvent the wheel.
IMHO: Microsoft decided that Apple and Android had won. So, they set out to copy them.
When my daughter first saw the Start Screen she declared, "Oh My, it's my smart phone."
When my son first saw the Start Screen he cried, "Dad, what do I do now!?"
It may be the fact that the key player(s), founders, of both Apple and Microsoft are no longer at the helm that this state of affairs has occurred.
The biggest thing that Windows 8 and (8.1) have done for me is to move me to the Linux families. I have shared my journey with some friends and family... and they are also exploring the move.... away from Microsoft.
By the way: Start Screen is not the only evidence that Microsoft decided to stop trying to be a leader and instead follower.... App Store is another major example.
Yes, there are pluses to the App store... but for Apple, Android, and Microsoft the plus is for their bottom line ($)... Linux Distros use a form of App Store... but it doesn't directly impact their bottom line... 'cause it falls in the "free" category. (Yes, I know free doesn't mean without cost... but really it does in many cases.)
I was an NT fan before NT 5 (aka Windows 2000), and very disappointed in the marketing move Microsoft made with the re-naming of their product and the general confusion to the Windows (95, 98, m) world. I was very disappointed with Vista, but happy that they "saw the light" with System 7. Then the force of Windows 8 was a slap in the face, and their "fix" with 8.1 is a joke.
[Yes, I have looked at reactos (NT like OS), but it is "still in alpha stage".]
Something better is on the horizon... just has to be.