Witness this article which said that:
Vodafone, NTT DoCoMo, NEC, Samsung, Panasonic and Motorola are joining forces to work on an open source operating system for mobile phones based on Linux.
To me, this says two things: first, that the handset manufacturers see that the money is in services and applications, and not as much in the handset or its operating system. Second, that they have no interest in paying per-set royalties so that all phones run on WinCE.
Interesting to see that Nokia, which is also interested in Linux for mobiles, isn't on the list...