The station density in NL simply doesn't allow for the same kind of high-speed rail that you see in Spain, France or Germany. The segments Groningen-Zwolle and Maastricht-Eindhoven are basically the only parts where train speeds over 200km/h make any difference. On all other trajectories, the limiting factor is not the maximum train speed but the interference from other rail traffic.

The major cities (Amsterdam, Rotterdam, Utrecht, Den Haag) typically have 4 trains/hour going between them. Higher-speed trains won't make any difference there, unless you first build out dedicated infrastructure (like the IC Direct line between Schiphol and Rotterdam, which cuts a whopping 20 mins from the regular IC travel time).