Yes, Roosevelt's New Deal created modern America, both politically and economically. Up until this time, social welfare, as it was, was handled by state governments. The federal government prior to the 1930s did not define its role as including helping Americans prosper economically or providing a safety net in times of distress. The crisis of the Great Depression, however, was so massive that FDR's government was willing to try what were then considered radical experiments in social welfare. For the first time, federal programs were enacted, such as Social Security, jobs programs, low-cost mortgages, and mortgage refinancing to help people avoid foreclosure. Rather than a patchwork of state solutions, these programs provided an umbrella for all Americans—at least all white Americans. The New Deal also established the 40-hour work week and a federal minimum wage, and it banned child labor. In other words, it was the beginning of the social order as we know it today. Much that we take for granted simply did not exist before the New Deal.
Because of these many programs, after World War II, a huge middle class was able to emerge in the United States. People could buy their homes with stable mortgages, earn decent wages, work decent hours, and know they would get Social Security and not starve in old age. People also knew the government had safety nets in place, so that if a crisis occurred, resources were available to tide them through. Life no longer had to be lived in fear. People were able to accumulate wealth. Young people could finish high school and go to college because there was no pressing need for them to start earning money at 14, 15, or 16. People had money to spend, and this in turn led to greater economic growth, in what is known as a virtuous cycle.