The platform is not the mistake. How is offered and how Team Windows Phone has treated cell technologies is what has been a major mistake. Treating GSM gracefully while throwing broken China Mobile based coding and cell network encryption to CDMA 2000 is unacceptable. You can have the Lumias, 8X, 8S, and Ativs of the world, but when focusing on one cell technology (understandable that is the choice on most countries) while disrespecting carriers in Asia and the US which use the other technogy (and have in mind Japan and US carriers are mostly CDMA based using Qualcomm standards) shows a lot of bias. Microsoft got it all wrong when it comes to CDMA 2000, and now have to get that coding fixed before summer when is supposed to meet the current Qualcomm standards and get devices on carriers like US Cellular, C Spire, MetroPCS and especially Sprint in the US, and carriers in Japan like NTT Docomo.
I know some of you will say CDMA cannot do talk and surf at the same time and that is a "dying" technology with no path to evolve. Do research on 1X Advanced, EVDO Revision B, and SVDO before making such assumptions. Those do exsist and are being pushed by the newest Qualcomm coding and encryption standards, which are becoming the rule in the CDMA world, especially in the US (both by carriers and by FCC recommended standards which can become a mandate). However, I will agree with many here that someday Qualcomm (and all the CDMA carriers) must find a way to unlock devices (I mentioned how it can be done a while ago on the unlocking devices ruling thread).