The iPod's only notable hardware that wasn't just a random off the shelf part was the click wheel, the chips were all off-the-shelf (until old iPhone chips counted as that), and iPhones didn't get custom chips until the 4.
So I guess the other part of the winning formula is "use market dominance in one sector to subsidize expansion into the next". I guess that's indeed one area where Google could reasonably try to be less inept, but I think all the institutional inertia makes that impossible by now. They'll go the DEC route of just drowning in their own internal problems until someone buys them up.
The iPod/iPhone yes, but "in the first place" the App Store was insignificant (the remenues at 2010 was < 2 billion dollars worldwide, so Apple's take was less than $600 million).
For comparison the iPod had that profit already in 2004, and around 3 billion in 2010 (when the iPhone had already started replacing it).
So, the App Store was hardly ludicrous revenue for its first 3-4 years, in fact less than 10% of Apple's revenue. The iTunes store even less so.
It's the iPod and then iPhone that made Apple's dominance. The big store profit came later (and the iTunes/Music profit never was that big).
So it's something they took advantage of after they grew (well, which company at their scale wouldn't ask for the best wholesale deals?), but not what made them big in the first place.