I don't think design alone, or technical skills alone are enough to get it done. Both are commodities. Anyone can throw up a spiffy iPhone app or web app with Node.JS in the backend. Not everyone, on the other hand has domain expertise, and can create a product with market fit, and sell it.
If you rely too much on your design skills, you'll end up creating something like Gowalla - something noone wants. if you rely too much on technological sexiness, you'll end up like SimpleGeo.. I bet they got 100,000+ lines of code altogether all for naught.
"If you rely too much on your design skills, you'll end up creating something like Gowalla" ...or you can build something like Kickstarter, which is a fantastic company, doing amazing things for others, and something that people want?
You can name plenty of companies with designer founders that haven't IPOed in the same breath that you name plenty of companies who had developer founders who haven't either. It's a bit unfair to say just because you rely on one aspect, you'll end up like a couple companies that have failed.
If you rely too much on your design skills, you'll end up creating something like Gowalla - something noone wants. if you rely too much on technological sexiness, you'll end up like SimpleGeo.. I bet they got 100,000+ lines of code altogether all for naught.