So what? They are obvious and natural competitors, battling for number 2 on the desktop. The point remains, the threat of free software like Linux is causing heretofore unthinkable partnerships, from Palm and Microsoft, to Sun and Microsoft, to Apple and Intel. Without the arrival of open source like Linux none of those partnerships would have happened. To think it was all simply simultaneous coincidence is laughable. IBM is the only major vendor contributing to GPL software, all others are either exploiting it, isolating it, or buying it and killing it.
So... unless youre a mindreader you have no factual basis for the statement "they did it because of Linux"