@evan yes! The primaries are super important to focus on, since they're when we have a chance to replace ineffective (or even collaborating) neoliberals with progressives. THIS is the time to fight like hell for the best candidates, not by withholding votes in the general.
IMO if the Democratic party stays under the forceful control of neoliberals, they will keep losing important elections. When polled on individual issues, US voters strongly support progressive policies.