20% of the general public in Poland, Mexico and some Eastern European countries don't agree with that claim. People forget how varied is the smartphone market across regions.
http://www.statista.com/statistics/245193/market-share-of-mo...
You see WP devices 'a lot' (that is: you get to see them once in a while) over there, but these are mostly owned by people who wanted some sort of smartphone. Also a lot of them are quite annoyed that there are no apps.
I would tend to think that market share is one indicator of a phone platform's popularity, and while 20% is not bad, it's not an amazing figure either.