Limits of populism?

Interesting article from the 3rd-wayish Progressive Policy Institute in the US on whether class-interest populism can provide an electoral base for the Democrats. It disagrees:
class-interest populists cling to an outdated concept of workers' interests -- a holdover from the New Deal-to-Great Society era, when a large blue-collar class was fighting for a fair share of the industrial economy's rewards. Today, most people work in offices or high-end service jobs and they believe their economic interests are more closely aligned with the companies they work for...[only] about 23 percent of the population can be categorized as having a direct personal interest in supporting the social safety net programs that most of the public strongly associates with the Democratic Party -- programs that help people living in poverty or just a few rungs above it. Democrats may protest the suggestion that they only stand for social safety net pro-grams for the poor; they may rightly argue that their whole social and economic platform is to the benefit of most Americans. But the hard truth is that most Americans simply don't perceive themselves to have class interests that strongly align them with one party or the other. That is, they don't believe that the direct, pocketbook benefits of either party's policies are so overwhelming as to outweigh all other political considerations.
The longer PDF of the entire article tries to estimate the (small) size of the social groups that would benefit by a populist agenda. On a first view it understates the size of the working class by equating higher credentials with higher class status. Still the paper is a type of analysis largely lacking in Australia, apart from the revolutionary left's attempts which I find even less convincing. I hope to work on this and suspect that the truth is in-between.
Update: Andrew Leigh has picked up on this article arguing that:
you can bet your bottom greenback the Dems are planning a median-voter strategy for the November elections. As UK Labour strategist Philip Gould once put it, a party whose policies are keeping its whole base happy is a party that’s heading to certain defeat.
Perhaps but then why are the Republicans playing to their base as argued in Off Center? Via Mark Schmitt a silly Republican argument for playing to the base.