According to the StackOverflow survey Windows has been losing developers for the past three years (though that's obviously not a new trend). So much that those stats say that there are about 2/3rds as many developers on OSX as were on Windows 7 (I don't know when 10 came out, but it's not represented).
IME if you're on a Mac at your day-job you on-average have a lot more freedom in which tools you're using, and you're a lot more likely to spend your own money on them.
All that just to say: I'd be very surprised if releasing for OSX first wasn't the best financial move for them.
According to the StackOverflow survey Windows has been losing developers for the past three years (though that's obviously not a new trend). So much that those stats say that there are about 2/3rds as many developers on OSX as were on Windows 7 (I don't know when 10 came out, but it's not represented).
IME if you're on a Mac at your day-job you on-average have a lot more freedom in which tools you're using, and you're a lot more likely to spend your own money on them.
All that just to say: I'd be very surprised if releasing for OSX first wasn't the best financial move for them.