Reagan won California by 16.78% in 1980, and 16.24% in 1984... so his margin was basically identical. the only difference was the country as a whole swung hard towards Reagan in '84.
He also LOST counties too. One of these counties was a reliable Republican stronghold, and might well have stayed that way if Ford types had stayed in power. After all, no Democrat since FDR save LBJ won this county. Many of the rich, elitist attitudes are still there in the county even now.
The next county, roughly the same thing, though it flip for Carter in '76.
But as a counter: The state was well on its way to being leftward before this point, if anything the Democrats desperate urge to keep the South cost 'em here. Frank Church or Jerry Brown would've flipped it easily in '76 where Carter failed. Either of their coattails would've kept John Tunney for another term too.
Also, just for funsies: McGovern won more counties than Carter '80 and Mondale.
In anything Carter rolled the clock back on the inevitable.
