Sadly, they already are, and long, long time, devoted fans at that.
I was a day-one adopter of the iPhone. It was a game-changer, no arguing with that. However, I was also a day-one adopter of Windows Phone. By that time I was already fed up with Apple and some of their decisions/handling of the iPhone.
I've been a software developer for over 20 years, and for a large portion of my career have been specializing in the Microsoft suite of tools/technologies. I know many developers, just like me, who have tried to stick by with Windows Phone and the promise of the amazing stuff coming up, just around the corner, just wait a bit more, etc. etc. Well, over the past year, these people have been falling off. Some going to Android, most to iPhone. I'm holding out for the next iPhone release to make the switch off my beloved 1520. Confirmation bias, I know, but when the die-hards are jumping ship, the game is up.