Agreed, a while ago I interviewed for a startup and got rejected even though I knew the stuff like book keeping were pretty easy to learn, but I haven't done before.
With the list of biz skills you mentioned, I've done more than half of them (I was a very active student). But you are right about "there's more people with business credentials that want a technical partner than vice-versa". The advantage I have I guess, is that not many people have as much passion to start a business as I do.