To be fair, the amount of effort that Apple puts into their APIs is well above the industry standard. Cocoa and Cocoa Touch stand with few peers when it comes to depth, breadth, and quality which has been a big factor in the success of their platforms. They’re some of the few SDKs where if you want to, you can produce a top tier app without importing a single third party library, which is no small feat.
In their shoes, even if the App Store didn’t exist, I’m sure I wouldn’t be all that thrilled to open the floodgates for lowest common denominator apps built with other toolkits that do nothing to leverage what makes the platforms good and unique.