Earlier quoted context omitted.
Sure I need a brilliant CEO, brilliant marketing guy, etc, etc. But first I need a great product. I'm going to make that, not the other guys.
You just might want to make sure you have some people interested in buying your "great product" too.
If a product is good and investors are convinced it has a market, they'll invest. Otherwise I'll need to move on to something more compelling. That's no reason not to try. Insisting on an identified market before starting on something would eradicate a whole lot of University research.