This places almost impossible demands on people. They must achieve unity, they must in large numbers be willing to place their own lives on the line to achieve what they can not expect to have more than near zero probability of success. If human nature were such as to make such mass uprisings more than the very remotest possibility, authoritarian governments (including our own) such as we know today could never have arisen in the first place.
If the Cuban people and army got mad enough at Fidel he would fall.