In this case it's more that almost the entire country is within a couple of hours of the Randstad. The whole country can act as a single economic unit, which isn't doable even in Germany, France, and the UK, let alone Canada or China. You can drive or take the train from Groningen to Eindhoven and back in a single working day with hours to spare; you can't even do that between Toulouse and Marseille, let alone further!

If anything it's a good thing - it means investment in Amsterdam benefits far more people than just those in Amsterdam.