By what metric is capitalism the "least worst" system? Most of the people who defend capitalism have to sell their labor and own zero capital. The result is a two-tiered system where the obscenely wealthy exist right next to a vast majority who don't have enough savings to survive a minor emergency. This is the situation in rich countries. The ongoing exploitation throughout so-called "third-world" capitalist countries also speaks against capitalism.

Moreover, if socialism is such a bad system, why did America fight tooth and nail to stop it? Diplomatic isolation, trade embargos, propaganda, political assassinations. It is because socialism actually threatens the profits of the wealthy. The west can't exploit the land, labor, and resources of nations that place the workers in charge of their own workplaces. Maybe if the most powerful country in the history of the world wasn't working against it the system could prove its worth.