and replace it with the election being won based primarily on turnout in California
No, it would replace it with a majority FPTP country wide system. Californians are a minority of the country. They do not get sole control, nor would they under a popular vote system.
California was larger than their margin nationally.
But not all of that margin comes from California, and not all of Californians vote blue.
Where you live should have no effect on how much of a voice you have in the federal government. Everybody's vote should be counted, and counted equally, because we're all made equally. The current system completely fails at that.