Good questions, Emily. If your comment box allowed for replies with unlimited length (I had to chop down my earlier comment), I might be able to get part way to an answer.

What I think great founders do share is a passionate belief in what they do. That's what drives them to do something that, in terms of probability of success, doesn't make any sense.

My jihad against exit strategies does not mean that I'm against thinking about the future. I think that's essential. But, to my mind, that future should precisely not be about "exit". That's for the house flippers (sorry, Rusty). The forward thinking should be about developing a clear vision for where you want to go -- what some people in the innovation consulting business (which I did for a few years) call a "desired future state". If the desired future is a pot of gold (or a secure retirement, or an assured salary, etc), then you shouldn't be in a startup.

What's important to understand is that the path to this desired future will be highly non-linear. It doesn't lend itself very well to elaborate planning. It's not an engineering problem. It's a design problem.