At the simplest level, economics can better show us the consequences of our actions. Less simple are cases in which we don't have the knowledge to predict the full consequences. Global warming and climate change are examples.
Capitalist systems function less well without state protection of investors, lenders, and companies against monopoly, deception, and fraud.
Liberal redistributionists in favor of heavy taxation place less weight on incentive than do small-government conservatives.
With less competition to fear, companies are emboldened to raise their mark-ups and profits. That lifts share prices and thus the wealth of already wealthy shareholders.
After a major loss of dynamism in the 1960s, productivity growth rates began dropping in most countries, falling by half in the U.S. in the 1970s and more or less ceasing altogether in France, Germany and Britain in the late 1990s.
Germany, Italy and France appear to possess less dynamism than do the U.S. and the others.