Well, Apple does have a culture of replacing a good thing with an even better thing (e.g., they killed the iPod mini when it was still the most top music player

Well, Apple does have a culture of replacing a good thing with an even better thing (e.g., they killed the iPod mini when it was still the most top music player on the market, to replace it with the iPod nano). But more importantly, they're in a position where they can set their own schedule for decision-making. They can take a good long time to think about (or test) changes internally before making them public.