Microsoft apps.
If Windows Phone have so much problem the app development should not go so fast:
"More than 100,000 apps have now been published in the Windows Phone Marketplace and new content is currently being added at the rate of 313 apps per day. At the time of writing, 100,145 apps have been published. Of these, 26,493 were added in the last three months and 9,391 were added in the last month. These apps come from just over 23,825 different publishers."
http://allaboutwindowsphone.com/news/item/14960_100000_apps_published_to_Windo.php
And Windows Phone Apollo is around the corner:
http://www.engadget.com/2012/06/04/microsoft-windows-phone-apollo-sneak-peek/
And Nokia probably will have some interesting smartphones ready for it:
http://www.concept-phones.com/nokia/nokia-lumia-evolution-runs-windows-phone-apollo-pretty/
The apps to Apollo be the same as in the current Windows Phone to. So in my opinion they already got a third ecosystem. I think if Nokia and Microsoft hold out it be same as the Xbox in time. They will get profit from it.