This is not the definition of a monopoly that courts and governments are concerned with; this style of monopoly is wholly legal. You understand that, right?The App Store is a monopoly on iOS. There is a marketplace for apps and services, and Apple has complete control over it.
I mean, if I walk into the Gap to buy jeans, I only find Gap Branded jeans. By your definition, Gap should be forced to sell Levi's to me within their store. But again, companies can be a monopoly internal to themselves. Do we really need to debate this?