How is the US Government keeping people poor? There are so many programs that provide financial or medical assistance to low income households.

Giving corporate welfare,tax cuts, and bailouts to mega corps. While not equally helping small businesses, in fact quickly shutting them down when they fail to pay taxes or get permits. Regulatory capture and certain regulations too, preventing people from ever breaking out and owning their own business. It's technically possible but practically not. So they (many blue collar workers) get stuck as working poor.

None of that has anything to do with Cuba specifically keeping salaries for their government workers and most industries below 1 USD a day, a common bar for poverty.

The question I responded to specifically asked about American scope.

You compared specifically limiting salaries for civil servants and most major industries to below the poverty line to tax policy.