Doesn't matter. The legal definition involves the ability to fix prices.
Consumors and developers are both free to run away from iOS to a variety of other platforms. If Apple charged a $10 fee for every app downloaded that would happen without a doubt.
Not a monopoly.
Europe already found Apple guilty of monopoly price fixing with iTunes. The ability to turn to other platforms is not relevant if they don't have significant market share.
Phazer