The school that Guinier describes is great. It also draws on a unique partnership and it only accepts students who want to be there. Is this scalable?
Lack of scalability doesn't mean you shouldn't do something. You should still do it if you can, but you are not fixing the wider society, nor are you building toward a transformation. You are just doing what you can to make something better and that is great. If she is writing on the virtue of doing the good that you can do, well, amen. If she is writing on transforming a system of higher education then I question how relevant this is.
Also, I am bothered by the fact that the high school only does college prep, not vocational prep. We need colleges but we also need vocational schools. Exulting college as the only path is a one-size-fits-all approach and that bothers me.