Interesting. I heard rumors about them possibly adding something akin to a start button back in 8.1, but there's no mention of that on this page.
No one cares about the start button. They care about the start menu. In 8.1, the button just does the same thing as hitting the winkey or clicking in the corner in 8 -- you get completely launched from the desktop environment, and go full-screen Metro-mode launcher.
While at first I thought it'd be the same (press winkey, type, enter), Windows 8/8.1 makes it far more cumbersome and is quite interrupting. Also, on Win8, you need to select what you're searching for. Unlike 7, it doesn't automatically search everything.
There is no way that MS actually thinks people want the button, not the menu.
We have decades of "click the start button" training drilled into peoples' heads. They'll find their app whether it's in a menu or a screen, but stranding them on the desktop without any button to get there was a problem. That's who the change was made for, not the tech enthusiasts that have been doing most of the complaining.
Apart from the grey background, there is a small bar at the top that shows for a clock and basic windowing stuff (tags, open windows, layout mode). There is also a start button like thing in the corner. Because I never use it, I tried to remove it from my desktop. Everything worked fine, but the desktop just looked wrong without that button in the corner.
I did however, remove the menu that comes up when you click on it.
This is fixed on 8.1, it searches everything by default.
People didn't like it because it was UNDISCOVERABLE.
As it turns out, the Start Menu was pure shit and everyone did Winkey+"Application Name"+Enter. And they still use it today.
It takes you to the Live Tiles screen. (I assume that screen has a real name but I don't know it and you get my drift)
[0] http://windows.microsoft.com/en-us/windows-8/start-screen