The difference in results across two developers can be incredibly pronounced; sometimes, those egos are very much earned.
Personally, I started a company without a business guy and no external funding. It was incredibly difficult to do without external capital, but we own it, and we're not beholden to external interests. We've hit a million a year in revenue, and are poised to completely eclipse that. I've had to step up to effectively serve as CEO and CTO, but without the code, there'd be nothing to sell.
I'm not claiming that 'business' doesn't matter, but rather, that compared to the people that imagine and then create the things you're going to sell, the usual business guy -- minus any other specific skills in the field in which he's working -- is a commodity.