I think Chris Sabatini has a really interesting take about why Cuba is not likely to be the next in a wave of dictatorial uprootings:
For the last two decades, from Eastern Europe to Egypt, none of the countries that has experienced a people's revolution has been under a U.S. embargo. Though it is about to be the target of focused sanctions as a result of its bloody response to the protestors (and deservedly so) before the current uprising even Libya saw its sanctions ended in 2004 by the George W. Bush administration. In the case of Libya --and in the past-- targeted sanctions tied to a specific act by the government can provoke a course correction or even collapse. Over the long-term, though, sanctions actually seal a country off from the rest of the world and allow a government to dig in. The inverse relationship between isolation and people's revolution is no coincidence. Contact with the outside world builds capacity and ideas insidious to even the most tyrannical regime.
Add this to all the other many reasons that the embargo helps to block political change in Cuba.