A so-called "technology leader" has a great idea, that works at the moment the great idea was hatched. This does not translate to the "leader" having an infinite stream of great ideas, and not prematurely, but at precisely the moment when they are indeed great.
Things change, and financial obstacles get in the way too. It's not just great ideas.
Take a look at Global Crossing. You'd think, laying fiber all around the world, for communications, would be a no-brainer. And they went under. Look at Blackberry. E-mail on the run. And the world has changed, and they're struggling.
Apple didn't reshape the whole industry. Apple was on the ropes, until they invented this fashionable smartphone. And then the derivative tablet. Basically ONE fundamental idea. Those came at precisely the right time, when improved 2G and then 3G had just become available. But who's to say that having a great idea at the right time means you'll have an endless string of great ideas, always at the right time?
I believe that the principal force at play here is the Law of Large Organizations, which states:
In any Large Organization, Loyalty will always be rewarded over Competence.
Once a Large Organization reaches a certain size, innovation will be squashed as Disloyal and Unmutual, and people capable of technical innovation will go elsewhere. Then it's just a matter of time before the money runs out.