The first iPhone had 128MB of RAM and ran at 412 MHz, underclocked from 620 MHz (https://en.wikipedia.org/wiki/IPhone_(1st_generation) ), and there was disbelief that what they showed could be built at all at the time with the advertised battery life.
They likely also didn’t want to commit yet to an API for third-party apps, as they didn’t know what was reasonable there.
Meh. make was genius. Makefiles were genius. pkg_install and pkg_add were genius. PMS was genius. RPM was genius. FreeBSD's ports tree is genius. pkgsrc is genius. Like nearly everything Apple ever did, AppStore is not at all original, not remotely the first, not by over a decade. It is really no different from any other binary package manager. It is Brew for iOS.
Like most Apple things, they weren't the first. Their genius isnt being first, it was spit polishing things to be simple for the masses. Over the years, they have lost a bit of that vision and turned googly with new products not quite replacing old products (how many times has photo sharing and backup been redesigned) but comparing the whole suite to components is a bit unfair.
if Apple had launched the app store with the iPhone, it would have had no where near as big of an impact as it did by waiting just a year. they created the demand first.
and no, Cydia was launched 5 months before the app store.
My only point is that the AppStore is not the Second Coming. It is and it only is a package manager. Just like all the others that came before it. And nothing more. It is not some searing example of genius. It is one package manager among countless. That it includes a payment system is an irrelevant detail.
What Apple did that is amazing is creating a community of developers out of nothing and gave them excellent tools to create software for their platform. It seemed overnight that the ocean of Windows applications, mostly due to obsession with backward compatibility, was no longer all that special.