Redmond, UI Drawing Board committee, early nineties:
"Where should we put the menu bar?"
"Where should we click the window to drag it?"
"Where should we put the close button?"
"Where should we put the minimize and maximize buttons?"
"And finally, where should we put the Start button?"
"mmmmh... Bottom left!"
Who made that decision may be the Inspector Clouseau of UI Design.
He's responsible for billions of km of useless mouse travel between to most important elements of the user interface.
A better place would be the top row of the screen, as the Mac did in '84:
But I suspect that it wasn't done due to a possible legal issue.
Now that widescreens are the norm, there's a better place to put the taskbask: the right side of the screen:
It's closer to the menu, the gadgets and, by taking up some vertical space, it allows more 4:3-like space to the windows.
Even Unity has its deadly sins too...