I personally know of one leading Japanese PDA manufacturer who had to abandon the product line altogether. It used Win CE. The reason you might ask was simply that they laid down an ultra high minimum volume licensing fee regardless of actual units manufactured. On top of this they stopped support for the specific microprocessor used by this company. BTW this CPU company is very much in business and quite a few of the embedded systems use it to run some version of Linux.

Another company came out with a similar product with embedded Linux as its OS. M$ arm twisted this company by threatening to withdraw all discount on their main stream requirement – Windows on PC. They had to delay the launch and redesign the product to use Windows CE – Pocket PC OS.