Word length is a better measure of brevity.  A lead section should not get bogged down trying to be too descriptive, too prescriptive or critiquing its conventional definition.     You could just say:

 Capitalism generally refers to an economic and social system in which the means of production are predominantly privately-owned and operated for profit.  Investment, distribution, income, production, pricing and other economic activity are usually determined by the owners of these means of production according to their own self-interest.  Almost all countries in the world have adopted elements of capitalism in their economic systems.