Pat, let me give you an example about why people of Cuba won't rebellion. I was born and raised in a country that is under US embargo. We don't have a communist government but a religious one. I can almost tell that 90% of people dislike that government but why they don't rebel? That's quite easy to find out. They once did to gain their freedom and end the 2500 years of kings ruling over this country. Now they regret what they did because what they got is quite worse. I myself wouldn't do it again. I don't want to risk my life and see some other asshole becomes the leader again instead of a democratic government. I'd rather we all make changes to this government to gain a 100% democratic one over the time. I don't want any more bloodshed. US embargo has been even in favor of the government because they can say if economy is getting worse it is the US' fault.
But as you said education has been getting better over the years. Media is under control and there is not much going on TV so kids are focused on their education. Specially girls are getting the education they want and they won't be distracted by issues like cheerleaders, beauty queens, prom queens and stuff like that because these kind of things are not allowed in schools. So if some people simply think it is a boring life they decide to immigrate to another country rather than rebelling. I myself got the best education one could get but I simply didn't pay a dime because best colleges are for free here and if you pass their test you get in. I sometimes think it is not that bad after all.