Most businesses are still on XP
By 2014 a new version of Windows will be out and I'm betting it will have an option to bring back the Start button. And as for most folks converting by then, most businesses are still running XP which is over 10 years old now. If you've never trained a bunch of people to use Windows, you can't imagine what a hassle it is. It's time consuming, creates costly errors while people learn, and is very expensive. Remember the saying "Make new friends but keep the old, the new are silver the old are gold". The start button and task bar are the old gold. Computers are productivity tools, not something to make folks have to reinvent the wheel.