Hillary dwarfs Bernie's fundraising, yet is remaining highly competitive. About as competitive as one would believe if they had the same finances.
People don't like to admit it, but representatives are usually pretty popular locally even if highly detested elsewhere. The US Congress's ~10% approval rating is only possible because local representatives maintain ~>50% approval ratings.
I believe the real problem is that people don't actually know what their representatives are doing. If people understood the level to which health care insurance companies were allowed to influence the ACA, I doubt a single supporter would survive reelection. Health insurance companies writing health care reform bills is pretty much the definition of evil in the US.