The market is all the places the devices are sold. So global makes sense. If you define the market as San Francisco then Apple might have a monopoly. But that feels a little like market gerrymandering.
Even if you were going to restrict to just the US, Apple still sells fewer than 50% of the phones.
Fewer than 50% is different from "Google sells twice as many"
> The market is all the places the devices are sold.
Certainly US regulators / courts don't purport to have jurisdiction over foreign markets, agreed? The aforementioned EU case against Microsoft was about the EU market alone.
Even if you were going to restrict to just the US, Apple still sells fewer than 50% of the phones.