The collapse of the U.S. economy has to be weighing on Trump's mind or the name 'Hoover' would not have come out of his mouth. He's worried that the Fed raising rates, which they normally do as the economy grows, will cause a recession.
He not only brought in more young people, he brought in more independents that often spoke of revolution against the two party system. He made people who felt alienated belong again, much the same way Trump had with his voters. If Sanders can ward off the mudslide of propaganda about socialism, he can defeat Trump. However, a hammer and sickle won't do the Democrats any favors in swing states.