I definitely think there's some truth to this, but there are more network connections involved here than a simple Seller->buyer relationship.

In my opinion, right now Apple is rocking the boat for 3rd party developers. Historically, that hasn't worked out that well for platforms, but we also don't have a ton of data to work with. It's conceivable that Apple becomes the "Company store" on Apple hardware, and their users only use Apple software.

But if that happens, I think they'll suffer more regulation and governmental interference (and rightfully so, imo).