Given that about a third of the country would identify themselves as progressives, it's hard to see if they gave of their own free will, there wouldn't be plenty of help to the disadvantaged.
But I rarely (never?) see any rhetoric in DNC politics about party members donating of their own free will to anything other than the Democratic party.
Virtue doesn't scale. Hence taxes for public good stuff because otherwise only the town with a generous Moneybags would have roads or a fire service (and the town with a racist Moneybags would only have a fire service in the white quarter). It's also hard to coordinate - see disaster response.
We're talking simply about charity. There are plenty of wealthy liberals - like Hollywood, Gates, Buffet, Silicon Valley, etc. All the people who donated to Sanders. Plenty of money to give to charity.
But I rarely (never?) see any rhetoric in DNC politics about party members donating of their own free will to anything other than the Democratic party.