I wonder if more inventions were born out of economic or other necessity (toilet paper?), out of the right combination of laziness with intelligence (TV remote), by mistake (the slinky) or out of the sheer drive to greatness (as would apply to most of aviation related inventions, I would assume). That would be a nice topic for a dissertation on history for someone out there, wouldn’t it? Although I assume the mix of historical, technical and psychological knowledge for such a paper would pose a challenge. Not even talking about how to collect and sort the necessary data.