The difference with Apple and other momentum stocks is that Apple isn't like Netflix, where hype deeply overshadowed the problem they have with increasing content costs, or Groupon, which simply has a terrible business model.
Apple makes an incredible amount of real money and real demand. In this 4th quarter, Apple will make more money than Cisco will throughout its entire year.
My concern isn't that people will all of a sudden stop buying Apple hardware... that simply won't happen. They will continue to make billions upon billions of dollars.
My concern is that there are a number of strategic missteps almost as soon as Steve Jobs died. I think the iPad mini will cannibalize iPad sales completely and I think a lot of strategic decisions appears to be fraught with confusion and desperation, like Apple Maps, releasing iPad 4 6 months after iPad 3, etc. I get the argument as to why they made the iPad Mini (my wife wants to get one because it will fit in her purse easier), but I still think very few will buy iPads, and they will need to double iPad Mini sales to make up for lost iPad sales, but I guess we'll see in January.
The major difference with Apple and a company like Microsoft or Cisco is that they don't have much recurring revenue streams. Most of their revenues come from consumers purchasing their goods quarter after quarter. In order to keep growing revenues, they really have to maintain their amazing pace of innovation.
If they make a really bad strategic misstep, and people slow down in terms of buying the products, it will show up immediately, and they won't have a strong enterprise pipeline to buffer them. In 2011, Apple sales were about $60B. In fiscal 2012, they were over $100B. So, could their revenues drop to $60B in a year? It's not probable, but it's possible.
That being said, their PE ratio is ridiculously low, something like 10x next year's earnings, and they have $120B in cash. They can do something ridiculous like buy Facebook or even Cisco for cash, and still have more money than most other companies out there, so there is a lot of room for dramatic and aggressive action by Apple.