There's a big grey area between two family businesses doing deals to help each other out and two dominant market players tipping the scales in their own mutual

There's a big grey area between two family businesses doing deals to help each other out and two dominant market players tipping the scales in their own mutual favor to keep out other players. Problems ensue when the behavior is anticompetitive, and when one or more of the parties engaged in the behavior have a dominant position in their market. This played out with Microsoft's abuse of its dominant position in the operating systems space to advance their browser ambitions. Apple presents a really interesting case here, since they pointedly do not have a monopoly on mobile app stores -- Apple's mobile business is a minority player measured by device count, and a majority player by revenue. IANAL, and not even really an armchair one, so I really have no idea if their majority-revenue position matters, or is sufficiently dominant, etc.