>HOWEVER- this is not the case in those counties delivering 86 electoral college votes that swung from Obama to Trump. To stay home outside CA (or to a lesser extent, states like NY) where there are no massive majorities, is to risk advantaging the opponent. This point could/should have been made to Democrat voters in Flyover country, but the smugees were so sure they had it nailed that there was no incentive to do anything that might affect HRC's certain trajectory. So she avoided the limelight while Trump took whirlwind visits to crucial counties who ended up giving him the win.
>

Good possibility, but it might be even simpler than that.
There's a good possibility that Obama's election was a blip on a trend.
State houses and governors' mansions have almost a 2 to 1 red to blue mix.
Both houses of the US congress are strongly red.

Going back further, draft dodger GW Bush, after having clearly demonstrated himself to be the worst president in modern times in his first term, easily beat John Kerry - with 3 purple hearts and a silver star - for re-election.

I rang doorbells for Obama in some minority neighborhoods. I've done a lot of canvassing and I've never seen anything like the zeal I found for Obama in those neighborhoods.
McCain and Romney never had a chance.
The closest I can recall was the zeal I found for JFK in Catholic neighborhoods.

It was easy to interpret Obama's wins as victories for Democrats when they were evidencing something else.