The aspect you're mentioing is the cost of political participation. The US is a country with a complex political and economic situation, where many different interest groups have to be considered. In addition the media, as arena to express and gather support for your political agenda, requires a high level of entry costs. Those are the conditions of a Democracy in a capitalistic system.
In Cuba too, there are costs connected to political participation. Any Cuban who wants to push through some agenda, still has to put a lot of effort/time into organising support for his idea and fighting for its implementation. The cost are of course not as high as in the US because the preconditions are different.
Probably the main difference is, that in the US interest groups, such as economic actors, have more importance in the political process. This however is legitimate in a capitalistic system because those actors represent important/valuable interests of the whole system.