This might not seem to make sense, but companies can be in just as much trouble when making insane amounts of profit as they can be when profits are low. It depends on HOW they have increased profits. If they have increased them by producing an even better product and with great marketing, then profits will continue to be high. But, if they have increased them by taking advantage of their user base and reputation, lowered the standards to reduce costs, and are producing a lower quality product than they previously did, then they are in serious trouble. This is exactly how a company creates a boom/bust situation. Sooner or later their reputation becomes forever damaged, and the enter long term decline.
Apple has done exactly this, if they aren't careful and don't do something quickly to change the direction they are headed in, they will damage their reputation as a company forever. When that happens, sales will decline on a much larger scale than is currently being seen. Apple is an incredibly vulnerable company. Their strategy of low sales with high profits on each individual item means that even a slight lowering of sales has a significant effect, and their use of vertical integration means that people tend to own either a bunch of Apple products, or none at all. Apple products are not nearly as useful on their own, they are designed to work as an ecosystem which is both a huge strength, and a huge weakness. A good example of the effects of this is with the Apple Watch. If you sell your iPhone, the watch becomes useless. People don't tend to just abandon one product with Apple, but the whole ecosystem.