In a way, gerrymandering is baked in to the constitution by way of the Electoral College. Consequently, the idea of democrats moving to already blue states like the California governor suggests does not help the cause. Most Republicans will be more than happy to have all Democrats living in California and Massachusetts because they will then easily retain power with less populated but electorally powerful states. The problem right now is that Democrats are too centralized in urban areas. Elections in the United States are not based on population, which is why Republicans win presidencies and can always have a chokehold on the Senate and instill minority rule.