MacWorld was canceled and one of the reason was that his health is deteriorating rapidly.
According to Gizmodo,
Steves health is rapidly declining. Apple is choosing to remove the hype factor strategically vs letting the hype destroy apple when the inevitable news comes later this spring.
This strategic loss will be less of a bang with investors. This is why Macworld is a no-go anymore. No more Steve means no more hype. Saying they are no longer needing [Macworld] is the cover designed by the worldwide “loyalty” department.
If you had remembered, Steve Jobs appeared thin and frail during the launch of the MacBooks a few months ago. He says he is ok but now rumours are flying in the Internet community.
I certainly hope that this is just a rumour. In my opinion, he is one of the biggest challenge posed to Bill Gates to make Microsoft better.