I agree with your criticism - it is a simplified model, and models only give a simpified view of the world. As you point out, ideally there are lots and lots of

I agree with your criticism - it is a simplified model, and models only give a simpified view of the world. As you point out, ideally there are lots and lots of criteria that should be considered, and that probably have a measurable effect. The big problem is getting the data to do so: You'd have to take some statistically significant amount of projects from the very start (which is where the most interesting part happens in relation to living or dying) and follow them closely until they either die or become successful. It would be an extremely interesting project though.