Your claim that the governments are dysfunctional is not provable. The US has been working for decades in both countries to do everything, including assasination of leaders and armed invasion to overthrow the government. We don't know how well either Cuba or Venezuela would be managed if we stopped trying to overthrow them militarily and financically.

How well would you do "managing" your household or business if every couple of years you were suddenly blocked from doing business or had your bank accounts frozen?