Yes, the court of public opinion says Steve is make/break for Apple. The related public, by the way, is growing in population as each new iPod, iPhone, etc. is purchased from Apple. And the court is getting increasingly vocal, varied, and
Ask any business analyst worth their salt - I'd imagine they'd say that Apple can do well without Steve, but it's going to be rough for at least the short-term without him as a mouthpiece/figurehead for Apple.
I think you can argue that this is a monster that Steve and Co. have developed themselves and now they're having a bit of trouble with it. Not that they can't handle it, but it's not pleasant to deal with sometimes.
However...if Steve were to step away a bit *someone* equally impressive, iconic, and creative would need to step up into public view to make sure the perceived relation between CEO of Apple and the customer base remains. I imagine Steve is doing this, if he's smart, behind closed doors at first - but he's gonna have to do start doing it on a public stage...and I recommend he does it soon.
I think there were more "non-Steve" presenters at WWDC this year, yes?