A revolution requires money. In Cuba you don't have money to save. It is true that there are people without money, but there are government management techniques that quickly dilute any attempt.

For example, in 1953 when those who are now in power, assaulted the Moncada and Carlos M de Cespedes barracks, they traveled from the west (Artemisa) to the east (Santiago de Cuba) in a 1953 Chevrolet, loaded with weapons that they bought or stole from gun dealers. I invite you to try to travel today. First, forget to have a new car, forget to get close to a weapon, forget to have fuel for the cars, forget to have money to finance a revolution.

When someone has a certain amount of money in their possession, the last thing they think about is making a revolution or changing something, they buy their ticket and leave. As @bitalion said, those of us who are still here, it is because of a lack of resources, or in other cases because of family issues that cannot be left behind.