There are reasons to be cautious about Apple, but not in this list. Most of the OP's concerns boil down to a perception that Apple has been 'too' successful, an

There are reasons to be cautious about Apple, but not in this list. Most of the OP's concerns boil down to a perception that Apple has been 'too' successful, and it's due for a failure. On the one hand, Apple's valuation is extremely high. On the other, their products are selling like gangbusters and the iPhone in particular has nowhere to go but up. The current emphasis on software and interfaces gives Apple a substantial advantage over the legacy players like Nokia and RIM; as the iPod showed, it's not a trivial advantage to overcome.