Yahoo! came first. Google came second. Where Yahoo! failed, google succeeded. Google is now King, and Yahoo! isn't even good enough to be its jester.
Sony and Microsoft have turned Nintendo into a pathetic afterthought.
It's one thing to achieve success. Keeping it, is an endeavor of its own.
Yahoo! and Nintendo are perfect examples of companies that allowed themselves to lose focus, among other things. Their initial success could not have been achieved without initial vision, and what they have been able to accomplish in their respective fields is commendable, but anytime somebody else comes along and pulls the rug out from underneath your feet, there are questions that come to the surface. Many of them.
The original NES was my first console. And even though Nintendo's direction has been lackluster for years now, the nostalgic power of their brand is helping them get by. I was a Yahoo! user long before I was a Google user. Hell, I even worked for Yahoo! for about a year when I was in my early twenties.
(I once plowed through a parking garage gate arm of theirs while trying to leave work and they had to pay for it. LOL.)
But I think that more than anything else, these organizations got comfortable. They reached success of epic proportions and figured success was theirs forever. Radio Shack? Circuit City? Blockbuster? 'Nuff said.
Success, if deserved, will come to you, but you'll only get to keep it for as long as you deserve to keep it.