The smartphone market was owned by Nokia and their Sxx series. That and the BlackBerries.
We were working on mostly Nokia (either native or Java), Qualcomm BREW (C++) and, granted, we had some demand for Windows Mobile but they were pretty much a nobody in that pre-iPhone world. Just as they're still nobody.
There was hardly any customer demand for Windows Mobile compared to Nokia and the others.
There has been no "transition" because MS never was anywhere that mattered with their phones.
It has always been an utter failure.
Now of course you may your definition of a "pre-iPhone Smartphone" which appears to be: "Certainly not a BlackBerry and certainly not anything that wasn't running Windows Mobile". So then it becomes hard to argue ; )