For many technologists, $39 is a very small amount of money relative to many things they could compare it to. (For example, the implicit cost of learning the new JavaScript hotness.) The audience of professional developers who can spend $39 is quite large. For example, if you're ever at a developer event, look for the folks with the hardware with the fruit on it; they're universally capable of paying $39. The fruit company does not appear to be hurting for market share.