Right out of Wikipedia:
Consensus historians of the 1950s, such as Richard Hofstadter, according to Lary May:
[B]elieved that the prosperity and apparent class harmony of the post-World War II era reflected a return to the true Americanism rooted in liberal capitalism and the pursuit of individual opportunity that had made fundamental conflicts over resources a thing of the past. They argued that the New Deal was a conservative movement that built a welfare state, guided by experts, that saved rather than transformed liberal capitalism.
Liberal historians argue that Roosevelt restored hope and self-respect to tens of millions of desperate people, built labor unions, upgraded the national infrastructure and saved capitalism in his first term when he could have destroyed it and easily nationalized the banks and the railroads. Historians generally agree that apart from building up labor unions, the New Deal did not substantially alter the distribution of power within American capitalism. "The New Deal brought about limited change in the nation's power structure". The New Deal preserved democracy in the United States in a historic period of uncertainty and crises when in many other countries democracy failed.
Leftists actually complained that FDR did not nationalize and seize the means of production when he had the chance.