I think you are missing two crucial pieces of the puzzle. The 3 months sprint and peer support. Those are the biggest outcome of an incubator. You work your ass off for 3 months to sprint towards a product while helping your peers with their sprints. This can be done without an incubator of course but incubator atmosphere keeps you going.
I agree that is very valuable, and there are other valuable aspects of the incubator experience that are omitted as well.
This schedule pressure and the support of colleagues can contribute to successfully creating a fundable opportunity.
I'm just saying that results should be the measure. Fundable and funded, and if that's not happening, the incubator is not working. Further, I put that result more on the program than the participants.