> Or the robust ecosystem windows mobile <6 had at the time?
Huh? Windows CE and, later, Windows Mobile had quite a large number of apps for its era since the programming model was similar to desktop Windows (pre .NET) meaning that there was a ready-made base of developers for it. They weren't necessarily easy to find since the idea of an app store (and Apple/Google eating 30% of your revenue) didn't exist yet but they were there.