The habit of pumping up projected growth numbers is been going on in most companys for a long time. The last thing you want to do is interject common sence into a board meeting when everyone else there is blowing sunshine up the CEOs A$$.
If you know anything about Apple, you'll also know that Apple has a long-term habit, in the past all the way up to now... of blowing past projections and doing better than anyone predicts... :-)
What you say may be true of a lot of corporations, but Apple actually does it... over and over again, in blowing past all predictions.
That's why they're the darling of Wall Street...