I just think the genius is in the fact that the guy knew there were enough people out there that would buy it. I mean, really? Someone can't use their hand to carry grocery bags?
I will admit that I've bought a good number of those reusable grocery bags. They hang on the coat rack for when we drag stuff with us wherever we're going. They're super handy and impossible to beat at a buck apiece. I would have liked to get a piece of that eco-friendly money.
I've sold many, many inventions in my lifetime, and marketed a bunch more. Of all things, a water-filled fake egg with a thermometer probe bought and paid for our farm. I came up with the problem and what I wanted to do, explained it to the family, asked for ideas, and my then six-year-old daughter came up with the solution.