They do have a better basic quality of life. That's exactly what they already have. Cuba is not a rich country like the US, so of course the direct comparison without historical context will mislead you. If they opened up free capitalism style trade with other nations, they would be slaves on foreign owned farms and foreign owned factories instead of the government (using this thread's definition of slavery, of course). If they opened up capitalism style free trade internally, some people would get very rich and the majority of people's lives would be much much worse off. The income inequality would skyrocket.
You're suggesting that they're poor because they're communist. That's not the case. They're poor because they're an ex colony whose never became rich from wars, imperialism, natural resources, etc.. And when you consider that and the US trade embargo, they've done amazingly well.
I'd like you to back that up. Right now, the private sector in Cuba (for example, taxi drivers with private licenses) is rich by Cuban standards. A taxi driver with a private license can make several times more in a day than a doctor makes in a month. Participation in the black market also contributes to quality of life.
The most successful common people in Cuba are those who engage with the freest markets.
But to blame Cuba's poverty on communism is wrong, it's a result of being excluded from trade. And I really wish you could pull back from the slavery hyperbole. They're not indentured servants. I work at a corporation, I make a bunch of money for the corporation that they pocket and then I get a tiny piece back, am I an indentured servant? What about my debt? Am I an indentured servant? Come on, just pull back on the rhetoric a bit and let's hash this out. And no one likes the hoarded wealth of secretive and bad people but that exists in America just like it does Cuba.
They're not chipping in, they don't have a choice in the matter. I think Cubans would rather have a better basic quality of life, than spend so much of their income training doctors who probably won't even operate near them, and who are used basically as indentured servants by the government, a government which pockets most of the money (as evidenced by the mansions and secret wealth of the despots).