I know this is an old thread, but I just saw your response. And... I don't quite know what to say, besides that it seems ridiculously offensive to the hundreds and hundreds of people that made Microsoft and Apple what they are.

I don't know what type of evidence you're looking for, and I don't know what it has to do with co-founders, but it seems pretty obvious to me that one person couldn't have designed every piece of Apple hardware or software or every version of Windows. That's why we invented collaboration - it gives extremely productive people a multiplier.