The fact that Castro has indeed prevailed for almost forty years only reinforces the belief that he will survive everything and anything. Nothing is more paralyzing than the lack of hope. Every totalitarian regime bases its power on the belief that any attempt to promote change is futile and will only result in the destruction of the dissenter. A totalitarian regime does not expect the love or the enthusiastic support of all the people, so they seek submission, conformity, and apathy. While some people believe the government when it says the U.S. embargo is the culprit of every problem in Cuba, many others can see through the government's lies.
Some people hate the U.S. as the arch-enemy of the Cuban nation.
In any event, the embargo IS NOT the reason for people's reluctance to oppose the regime. The question is how to strike a balance between helping the Cuban people without helping the Cuban government. That is precisely the predicament for the U.S. and the Cuban exiles. My suggestion would be to isolate the government as much as possible, very much like what the international community did to the racist government in South Africa, while at the same time showing open support for the freedom of the Cuban people and its right to democracy. Most Western nations are NOT doing this now.