Either it pays off to take a dependency on Apple or it doesn't. The costs of the dependency are both short-term - building apps for the Apple app store and supporting Mobile Safari - and long term in the form of Apple changing it's "API" arbitrarily in ways detrimental to your business.
My point is that your business model is what you can control and change and the odds of changing Apple's business model without changing the nature of the market are zero. Changing your business model can change the market.
Finally, if your business's customers are more loyal to orthogonal aspects of Apple than to your business then it is better to think of those customers as Apple's rather than your business's. There's nothing to be gained by wishing it were otherwise.
My point is that your business model is what you can control and change and the odds of changing Apple's business model without changing the nature of the market are zero. Changing your business model can change the market.
Finally, if your business's customers are more loyal to orthogonal aspects of Apple than to your business then it is better to think of those customers as Apple's rather than your business's. There's nothing to be gained by wishing it were otherwise.