This structural/automation-killed-the-worker story is without evidence.  Middle class balance sheets were devastated.  Our economy is 70% consumer demand.  When consumers don't have money, they can't spend money.

Furthermore, modern technology has not made the worker obsolete.  People have been making such claims since Sam Slater.  The truth is that technology is the driving factor behind modern economic growth precisely because it makes workers more productive.  For some reason, some people conclude this must mean the worker is doomed, as if eventually there will simply be one machine with one operator doing one job - the rest of us miserably unemployed.  In reality, technologically driven increases in production are what make the pie bigger.  Go ahead and look for modern economic growth before the Industrial Revolution.  It didn't really exist because of fairly static limits on population and capital.

Moving along, all governments have debt.  The issue is not the presence of debt.  The markets want as much of our debt as they can buy presently.  The issue is that people don't understand that the issue is not the debt.  The only thing that matters vis a vis our current debt situation is that the economy grows while debt shrinks.  The nation is not a household.  It does not need a short-term strategy to retire all national debt.

Government can't afford to pay for big ideas without a robust middle class paying taxes and sufficient jobs to lessen the amount paid out for the safety net.

This is only true in the long run.  In the short run, we have essentially zero borrowing costs right now.  The government can afford it presently.

There are solutions out there, but maybe the problem is that left-liberals still can't diagnose the disease.  Obamaism's embrace of debt hysteria certainly doesn't help.

I think they talk about safe topics. Health care (but not single payer) is safe. So are immigration reform and voting rights. "Safety net" is vague and inoffensive minus the details.

Is that all they want? I doubt it. I think that most Democrats want gun control, but you hardly hear a squeak about it in Washington. Not a winning issue. Cap-and-trade? Another policy-non-grata. These are not radical ideas. They are liberal ideas that have been hushed up and pushed to the margins because they're unpopular. There are exceptions of course, and I'm sure you can find Democrats who espouse these policies, but they don't represent the party mainstream. In the party platform, you'll only find namby-pamby references that express concern about global warming and gun violence without substantive proposals to address them.