Obviously Google Android has been around just a little longer than Microsoft Windows Phone 7 and we don't have a tally on how many Pocket PC and Windows Mobile apps are out there but odds are, its already an impressive number. But the difference between those apps and the hundreds of thousands of Apple and Google apps is, none of those Windows apps were assembled in a source store like the ladder apps.
Desktop-as-a-Service Designed for Any Cloud ? Nutanix Frame
The difference between Google, Apple and Microsoft apps