You missed my point, my point is that many people have their work built around certain programs and often those programs are unique to one OS, hence why an OS isn't interchangeable for many people, at least without significant cost involved.
And for most people that OS is Windows, considering that it has roughly 90% market share. KnightWRX is 100% right, most people don't need a specific OS for their workflow.
If you
need a certain OS for your workflow, then I would say you are in serious trouble, especially if that OS happens to be OS X. Apple has a monopoly, no-one else is allowed to sell computers with OS X. We have already seen Xserve being discontinued and I would say Mac Pro is next on the list. Even if it doesn't get discontinued, it won't get much love from Apple, meaning that it will use outdated hardware and cost a hefty premium over other systems. It's quite obvious that Apple doesn't care much about the pro market.
Usually, pros are the ones who have a workflow that may require a certain OS. That is the only reason why Mac Pro is still alive. What happens if/when Apple doesn't offer a computer that suits your needs?
Like KnightWRX said, web browsing, email and IM can all be done with in any OS. If someone chooses one OS over another in that case, he is simply doing it because of preference, not because he
needs that specific OS to accomplish his tasks.
