Marketing is about psychology and these two companies are very good at it (especially Apple). It's how they continue to create new revenue streams for themselves. Instead of selling the whole package. They'll split it and sell it seperately, explaining to you how it all fits together.
And we buy it always. Once we get hooked, we get hooked!
This is the best way to put it. Lol at this point, we’re Apple junkies getting our kick from the thought of owning the latest device.