-- Dr Linda Lewis (Columbia University College of Physicians & Surgeons)
Google has been working on their automatic car tech for ~5 years. Amazon has been working on the kindle line for ~7 years. Google's project glass took ~4 years and they've been working on social for ~3 years. SpaceX on the falcon for ~5 years and Tesla Motors on the roadster for ~7 years.
Sometimes the better thing to do is quite literally do nothing before you go pull off a Nokia like move (sucking up to the losing horse in mobile) or the like. That doesn't mean pull a RIMM either.
This kind of thinking isn't very good because it completely disregards the uncertainty present in product development (http://en.wikipedia.org/wiki/How_Doctors_Think#Disregard_of_...).