No doubt there's some iPhone cannibalism but, in the end, the iPhone is a huge net positive for Apple. Also, don't write off the iPod just yet. Not everyone is going to buy a iPhone/Android/whatever. Unit sales are essentially flat year over year despite the new crop of improved smartphones.
2) The whole investing thing is about growing profits. If a company doesn't grow then neither will its value. Microsoft's share price is flat over the trailing 5 years yet Apple is up 400%. That's no accident. Hey maybe you're risk averse and don't care for the high beta of a fast grower and that's cool but I wouldn't be chalking up Apple's success to faddish products.
iPod has been around for 9 years so I don't see how that's a fad. If people are switching to a converged device then it's mostly to the iPhone. I guess that's a fad too.