Kevin Drum observes:
As for the broader electorate, they don’t care much about broad economic growth either. They care about their own paychecks. This means that if Democrats want to win them over, they need to support policies that support economic growth and channel that growth largely toward the working and middle classes. Those are separate challenges, but without them both an agenda dedicated to economic growth won’t really do us much good.
I’m not really sure how separate they are. I think the specific fate of the very poor can become pretty unmoored from overall economic conditions, but certainly as a historical matter middle class incomes have risen the most at the same times America’s has had the most rapid economic growth—the 30 years after World War II and the late 1990s. You can construct some models in which this isn’t the case, but in practice the basic mechanisms for faster economic growth lead to rising middle class incomes, though not necessarily rising incomes for each individual middle class household.