I think the gaping hole in the Democrats' economic platform is what to do with the working class in rural areas. They are not only not communicating with these people well, they are also not presenting viable alternatives to tradition natural resource based industries and agriculture on which these people typically thrive. And installing solar panels on rich people's roofs is not a viable long term solution.
Democrats, while purveyors of education and the sciences, have fallen victim to the lobbying efforts of "softer" industries like software development, content creation, and banking. They have not kept up in representing the more physically-based, "hard" industrial areas of the economy. The mistake is putting all their weight behind currently non-viable renewables for base load power production like PV and wind turbines while dropping the ball on the advancement of nuclear energy, which is the real solution in the short to medium term. We fucked up big time in this regard, and now the fossil fuel industry (I.e., coal, crude, and natural gas) is going to fuck the world up massively.
If there is a single giant gripe I have with Democrats, it is this. Pushing full on nuclear energy would have massively bolstered the economy, curbed climate change, and made electricity abundant and cheap, paving the way for another revolution in moving to full on EVs in the transportation sector.