It depends how you look at it. Worldwide you are right but Android dominates largely due to the availability of cheap handsets (most of which aren't running the latest Android with the modern flat design style).
In the US iPhone is 40% of the market and considering that 80=90% of users have upgraded to iOS 7 the number of iOS users that are using the flat design compared to the number of Android users with flat design is probably a lot closer than market share would indicate.
Also, although they have less than 25% of the market they are still the second largest manufacturer which in my opinion makes them a 'major hold out'.
