Is it possible that if you create a capitalist market for water, poor countries without any coveted natural resources will never be able to pay enough for water?
Such places may exist but I am not aware of them.
Look at every major city in the world.
They are all reliant on a reliable, major water source.
Notice how many cities exist on rivers or near lakes? Not a coincidence.
There's other things that predict growth -- suitability for trade and the presence of a hinterland -- but water is the best predictor.