It's also that good marketing of a product is probably more integral to its success than its engineering. There are so many stories of superior technologies failing because of bad marketing.
I agree that marketing is extremely important. There is no product without the engineers and no customers without the marketers. If you prioritize quality, I think the engineers are more important. If you prioritize making money, perhaps then the marketers are more important. I don't really know.
The problem is that in this particular case, the only things this person seemed exceptional at were being friends with the CEO and being unpleasant to work with.
IME at startups (well very small micro startups) you focus on quality at first, and wait for the company to go bankrupt. Then sell the IP to another company you happen to own. That second company focuses on marketing without having to worry about the ownership %'s afforded to the engineers at the first company.
The problem is that in this particular case, the only things this person seemed exceptional at were being friends with the CEO and being unpleasant to work with.