I agree with you to a point. It is true that colonialism provided the Europeans with cheap raw materials and agricultural products that fueled the industrial revolution. Colonialism represented a zero sum gain — the Europeans gain was equal to their colonies losses, in terms of natural resources. The Europeans weren’t interested in trade, they simple used military force to take what they wanted from the indigenous populations.
If we change the scenario and imagine a world where the Europeans respected the sovereignty of the underdeveloped world, paid for the resources, helped to establish good systems of government and legal systems, allowed for local taxation to provide government services, invested commercially in these countries, trained the workers, etcetera… all designed to advance their societies, then I believe that the third world would look much different than it does today. For the better! And in the final analysis Europe would have been better off too!