That may be true at first, but when they have a huge part of the market... they could argue: "without our customers, you wouldn't have that many users". Kind of like a chicken and egg situation. When they already have such a large slice of the pie, they start to care mostly about the bigger app developers, and the small ones are just something they need to show big numbers, but they are not that important anymore...

(Just to be clear: It's not that I think they are not important, it's what I perceive as their attitude when things like this happen)

They are dependent on developers as a whole, but not on any individual developers (with perhaps a few exceptions).

The iphone sold in those numbers even before there was an App Store.