I’ll take the bait and entertain you:
The theory that CA is "maxed out" for Democrats was always silly and didn’t even make sense when Trump's position was less catastrophic than it is now.
That said, I don’t think OC and Westchester will be what Democrats will be patting themselves on the back for on election night if that margin is accurate. DFW and Houston, though...
What does the margin in California tell us about election results in Texas or any other state? Hillary Clinton had the best margin for any Democrat in California since FDR and she still lost the national election, lol
Do you think it’s a coincidence that in that same election TX and CA had a virtually identical swing / trend toward the Democratic Party (CA: D+6.9%, TX: D+6.8%)?
Do you also think it’s a coincidence that the result of applying the same 2016 -> 2020 swing this CA poll is indicating to TX is a tied race in TX, which coincidentally is exactly what current TX polling (which has been very reliable in recent election cycles) is showing?
Do you think there might be other explanations for this pattern than "local or some other idiosyncratic factors"?
That’s right, because there’s no local or otherwise idiosyncratic factors that could be driving Biden’s margin in a non-contested, super safe state of 40M that aren’t perfectly exportable to any suburb in the country.
No, there aren’t, actually. Certainly not in the urban/suburban areas you’re envisioning, and certainly not with a swing of this magnitude, much less in two consecutive elections. "Nuance" is nice, but not when said "nuance" amounts to nothing more than a thinly-veiled attempt to deliberately distort the big picture.
And this...
The only demographic propelling Joe Biden to those margins in California (in only one poll, no less) is Californians, lol.
...isn’t helping.