The reason economic growth is so slow right now under the democracy of the United States is not because of the framework of democracy itself, but because of how worthless the people carrying it out are. If the two parties in Washington would stop act like such entitled weiners and go back to doing their job, economic growth would be much more observable right now.
In a democracy, although I am not sure a true one really exists at this point in time, people all take responsibility for governance. And therefore they are going to be concerned about all types of growth for all types of people, including themselves. They are going to be thinking of ideas for businesses that will lead to this type of prosperity.
As Abraham Lincoln, the 16th president of USA had proposed that "Democracy is for the people,of the people and by the people." It advocates that democracy is not for affluent people only. It talks bout the normal middle class for which economic growth is not of major concern but Eco. Equality is more significant.