The idea that the colonies were money losers is an empirical claim, which in the case of the Netherlands as in case of the UK is completely off base. Some colonies in Africa in the late imperial age may have been money losers, but most colonies definitely were money producers. Just start looking into the kind of active industrial destruction the British enacted in their Indian colony to enhance their early domestic textile production to get a historically accurate idea (in place of an a-priori reasoned free marketeer idea) of the situation.