Well, while they desperately try to keep shareholders happy instead of developers, Nvidia racks in trillions in market cap. But I agree in the sense that thinking ahead further than the next quarter is not a great strength of most publicly traded companies.
Supporting... I remember this Freakonomics interview with Ballmer about his statements about the iPhone:
"There’s two things: What would I have said differently and what would I have thought differently? They’re actually quite different."
Companies really only admit to failure if there's no other option and the pressure is too high ("Antenna gate" and others come to mind).