The simplest and most plausible explanation comes from, of all people, John Dvorak
One of the mysteries surrounding Steve Jobs’ decision to hand the CEO title over to Tim Cook is its timing.
The assumption underlying most of the commentary these past two days is that Jobs must be really really sick — which is understandable given the wording of his letter of resignation. But is he that much sicker this week than he was last week? Or last month? He’s clearly not on his deathbed. By several accounts he spent much of the past two days at Apple AAPL headquarters.
In his “Second Opinion” column for the San Francisco Examiner, John Dvorak — a man whose penchant for contrariness led him to suggest in 1984 that nobody would want to use a mouse to control a computer and in 2007 that Apple “pull the plug” on the iPhone before it’s too late — offers a simpler, more logical explanation.
“The reason,” he wrote, “is Tim Cook.” The key paragraphs:
As one of the commentators on Investor Village’s AAPL Sanity board wrote, even a broken clock is right twice a day.
UPDATE: The Form 8-K that Apple filed with the SEC Wednesday to register Jobs’ resignation includes this provision: