So, for the same profits, we had a stock price of 420 this time last year and ~515 today. So, you automatically assume 420 was the right number and 515 is not, and that it will head toward what you think is the right number? Got it.
But to justify a higher price today you would have to believe that apple is more competitive in the overall market this year than it was last year and I don't think it is.
Also, growth of growth is flat, not actual growth which is still quite positive.
Last year they made $25 billion, this year they made $41. But of course the rate of growth is smaller than the year before last when they only made $14 billion. This according to Wall St means they are failures.
Lets put it this way, APPL's earnings growth is twice GOOG's total earnings.
No, it doesn't. (edit: they are failures when it comes to keeping up their growth rate, yes.) But if previous stock price was arrived at by assuming rate of growth would stay constant, the stock will drop if rate of growth drops, as according to best available prediction the company will be worth less in the future than you had previously expected.
Stock prices are influenced by all kinds of predictions, guesses, and voodoo for present and future. It's a good idea to not to attach too many personal feelings or judgments like "winner," "best," or "failure" to the stock for this reason.