Well..My first reaction is "Meh".
Things you go to know. The startup who incubated in university incubation center are lobbied heavy by the student fraternities. If you are not part of it, you are probably not going to get in. Talking about rockstart and others, they do not really have enough talented startups. Ofcourse there are exceptions. Also, do not forget the government subsides that "sustainable" startup get.
According to me, the dutch startup scene is like any other european startup scene. Theres always few success stories and alot of failures.