If Steve Jobs didn't have Woz, he would be a used-car salesman right now. Woz essentially invented the PC. He could find a thousand people like Jobs in any MBA program. Sure marketing is important, but it's frosting on the technology cake. If you get the technology right, the marketing will follow.
I have no particular love for YC, but let's be fair. They are interested in things people can use, especially web apps. Things it might be possible to make money off, one day. While I love CouchDB and use it every day now - it's not an end user kind of thing. I'm not really sure what it is. Apache is a pretty good home for it, IMO.
In fact, all the great, innovative startups were a Woz or Woz/Woz combination. Ok, except for Apple, but again, Jobs really only added value later by playing VC. The seed level was a pure Woz play.
of course you are right there aren't a thousand people like jobs, you'd be lucky to find 1, but the point of it is that there are plenty of people to fill his position, you just want to find half his brilliance. however, if your product is abysmal crap nothing will save it, not even Jobs. In fact part of the reason Jobs is so good is he'll cut your product, and you, for doing a crappy job.