I'm very sympathetic to the intelligent arguments that people like Virginia are making that you have to help people downballot and you have to arm yourself against people like the Kochs, but the strategy of fighting fire with fire that the Democratic Party has used for the past 2-3 decades hasn't really worked, it's simply resulted in a Democratic Party that has had to by necessity move further to the right on economic issues/become much more corporate/crony capitalist in order to get "wins."
This is a "winning" strategy in the short-term/from a political standpoint, but a losing strategy in the long-term/from a policy standpoint.
The Democratic party moved to the right during the previous decades not because of the influence of big money but because whenever it fielded left-wing candidates it kept losing by landslide margins (McGovern, Mondale, Dukakis).
On the contrary, despite being the party who benefited most from Wall Street money until 2008 it didn't hesitate to enact Dodd-Frank which permanently alienated many of its big donors and sent them into the open arms of GOP.
I refuse to believe that, in either of those three situations, the candidates lost because they weren't big enough fans of deregulation, laissez-faire economics, and crony capitalism. McGovern lost because of Vietnam/crime, Dukakis lost because of being soft on crime, and Mondale was tied to Carter, and all three were very uncharismatic candidates perceived as weak on foreign policy/law and order running against highly unfavorable fundamentals.