Literally — the world feeds from the bounty of America’s capitalist liberty. Leftist young students buying those cutesy fluff degrees, read this National Review article. See how American farmers feed the world while you browse for “fair trade” logos. See how capitalism works. Maybe consider getting your hands dirty.
Because, capitalism is not a system, as your Marxist professors have told you. Capitalism is just what free people do when they get up in the morning. And, freedom motivates them to do it well.