Yeah, not really sure it was that important that CA was below the national average. Remember, despite more simplified storytelling that our history books prefer, most of the South was the slowest to come around to Reagan (Carter almost won nearly every Southern state with just a final push/doing a little better in the suburban areas), and the South tends to have the wildest swings. Dixie finally coming around in full force in 1984 was going to make a lot of solidly Republican states in the North and West look comparatively "less Republican."
The sheer number of narrow victories Reagan won in the South in 1980 remains, I think, one of the most remarkable electoral facts of my lifetime. I think Carter won the combined PV's of MA, RI, DE, MD, DC, WV, KY, TN, NC, SC, GA, AL, MS, AR, and LA, but of course Reagan won far more EV's from these states.