Karl Marx believed that the structure of capitalism at his time was doomed to fail. In last century, during the Great Depression, combining with Keynes's theories, it could be concluded that in an economy, if Aggregate Demand is less than Aggregate Supply, it is a more serious and common problem. After nearly 200 years, although capitalism has changed significantly, including innovation, changing of workers' welfare, rapid development of technology and globalisation... Can we still say, the core problem of capitalism: AD is not sufficiently enough, is still a problem? Does this mean that Hayek, on his ideas of 'no government intervention', is wrong?