Scott McNealy said early on that retreating to the Data Center was where companies went to die. And at the time was selling workstations on desks and crushing DEC, then when that business got eaten away by Windows the data center was where Sun was going to make its stand. And then it died.
I think a lot about what the fundamental principle is here. How do seemingly invincible forces in the market get killed by smaller foes? Christensen's Dilemma doesn't really explain it, it describes it, but it doesn't tease out the first principles behind it.
At this point I think it is a sort of Enterprise "blindness" which was something Steve Kleiman at NetApp shared with me. A company can be so good at something that they focus all their energy on it, even when it is vanishing beneath them. Consider a fictional buggy whip company when automobiles came on the scene, right up until the last day they made buggy whips they could be the best whip you could buy, all the secrets to making a great buggy whip where mastered by this company, all the "special sauce" that made them last longer, work in a wide range of conditions, and yet the reality was that the entire reason for buggy whips existing was evaporating with the loss of carriages. By focusing on what the company was the undisputed leader in doing, they ride the wave right into the rocks.
When the company is so stuck on what used to work for them, even after the technology has moved on, they become blind to the dangers. Challenging to watch, even harder if you feel like you can see the train wreck coming. And of course soul crushing if nobody driving the bus will listen to the warnings.
The next sign I'm waiting for is Apple to ship a Macbook laptop with their own 64 bit ARM processor in it. Then it gets really really interesting if AMD can pull off an ARM server chip, going where Intel won't.