The changes in the economic system that Marx and Keynes conceived were based only on the organization of resources, production and exchange. No attention was paid to the change in man. That is why the system of Marx led to dictatorship that destroyed the entire system. The end-result of Keynesian system is that production is achieved more for the people but less for peace and satisfying hunger. If a considerable amount of effort had not been directed to destruction, the problem of poverty and unemployment would not have got aggravated.
The question then is: how is this possible? When man has feelings of fear and urge for greed, these get extended into sovereignty and hatred. When there is the urge for considering oneself as superior to others, why would one bother about satisfying the hunger of the people? One would be keen only to build power. And the building up of power inevitably leads to destruction.