The demerits of capitalism are that our current version of capitalism is in violation of the most rudimentary principles of freedom, and thus yields a stifling oligarchy built on the backs of monetary enslavement, in-turn leading to a vile-maxim of excessive consumerism by a powerful few, hence becoming non-renewable and therefore highly erosive to the evolution of mankind.
But we can and must reinvent capitalism to obey to the freedom of freedom that deploys an evolutionary meritocracy. Quite easily by subjugating capitalism to a few new rules of the road, the kind of rules nature implicitly applies to all species. Rules we best apply to ourselves preemptively before nature applies hers with less grace.
