Let's consider the economies of Communist nations. I suggest we take into account a bit of regional history.

By any measure, China has come a long way since the Communist regime took over in 1949.

You could say something similar about Soviet Russia. By the 1980s it had stagnated, but the average Russian was incomparably better off than in 1917.

How far have Russians come since then? Has capitalism ushered in a golden age of prosperity and well-being? (Here's a clue: life expectancy peaked in 1986. Russians lived longer 40 years ago, under Communism, than they do today.)

Vietnam has done reasonably well since other countries stopped invading it.

American foreign policy hasn't done much for Cubans, either. Especially in the last few months.

Castro and Ho Chi Minh will go down in (our) history as Communist revolutionaries, but they weren't fighting against capitalism. They succeeded by uniting their people against colonial rule.

(Slavery ended a while back, as you are keen to acknowledge, but Cuba was a US colony until 1959. Puerto Rico still is.)

I'll grant you North Korea is a basket case. But it is arguably a monarchy.