As a general rule, it's most cost-effective for a handset maker to pick one smartphone OS to build for and stick with. Nokia uses Symbian, RIM uses BlackBerry OS, and Apple uses the iPhone OS. Those three companies are the biggest names in the industry right now, and it's possible that their decision to stick with one OS is part of that.

Motorola certainly seems to think so. In an interview with GigaOm Motorola co-CEO Sanjay Jha 'stressed' the fact that the biggest handset makers in the industry were 1-OS developers. There are currently no Windows Mobile devices in Motorola's coming line-up, and it's possible that we'll never see another WinMo device come from Moto.

Windows Mobile and Android are essentially competing for the same groups of customers, and the continued success of the iPhone makes this demographic smaller every day. Manufacturers are increasingly betting on Android to win this duel between operating systems. HTC and Motorola have already bet a lot on the success of Google's OS, and it's likely that we'll see the enormous growth in Android smartphones come at the expense of Windows Mobile.