"This [IDC prediction] might come about, but I think the forecast is on the optimistic side given all the turmoil and transitions that need to take place in the next four years to make this happen, and the fact both Nokia and Microsoft need to execute flawlessly -- something they have not been known for in the past," Gold said.
Nokia, which has brand loyalty outside the U.S., might not remain so popular abroad with the Windows Phone partnership, he added.
In IDC's defense, Llamas reiterated some of the same themes as other analysts. "Nokia is a world-class manufacturer, so when they click the switch on Windows Phone, it's going to be on," Llamas said.
"Nokia is well-known outside the U.S. and we in the U.S. are very westernized," Llamas added. "The iPhone really is the standard here and Nokia is not really heard of. But in all other parts of the world, Nokia is the out-and-out leader, from Latin America to Europe, Middle East, Africa and Asia. That's everywhere but North America.
"Nokia is number one, and even if they got a fraction with Windows Phone of what they got before when riding high with their Symbian OS, they will be that much better when Windows Phone is out the door," Llamas added.
amas also said that carriers will also want Windows Phones as a way to round out their product lines beyond Android devices, iPhones and BlackBerry devices.
Microsoft's Windows Mobile OS "didn't work" as a smartphone OS and "that set them up for challenges," Llamas said, conceding a debate point. "But Windows Mobile was a PC OS shoe-horned into a mobile phone, while Windows Phone 7 is designed for phones." The early lack of copy-and-paste functions "doesn't spell complete failure," Llamas added.
Even though IDC has Android hitting the top spot this year and staying there in 2015, Enderle wasn't so sure that will pan out. Android could be vulnerable to lawsuits from various parties over intellectual property and patent disputes, he said.
"Any forecast for 2015 really depends on Android," Enderle said. "I count 37 different lawsuits against Google over Android IP, over all bases." Google has become a target for Android lawsuits, partly because of its success, but that doesn't make the lawsuits weak.
Enderle believes that Windows Phone's biggest obstacle will be the iPhone, not the others. "Beating Apple would be a bitch, but moving around Android and RIM is very possible," he said.
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