The urban exodus has been occurring for a long time.
Urban real estate is limited. Cities grow no longer.
AC, roads,electric and good cars have made rural /suburban living desirable.
Demographicly, it is a long term trend ... all the net gain in congressmen is occurring in rural areas, reducing urban congressional representation.
Reflecting the population shift, 8 more electoral/congress seats pop up in red rural areas in 2020 ... with blue cities shrinking 8.
Since 1992, each election cycle has seen an increase in counties picked up by the conservative candidate ... even when they lost.
At some point, the demographics of rural power would exceed urban ... it was just a matter of time.
Hillary just speeded it up with the deplorable comment.
Nobody was picking the "better" candidate ... we all picked the one that represented us ... rural picked Trump ... Urban picked Hillary.
And that is how it played out on election day.
As to california and the electoral college ... mathematically, it is a dispersion of voters you need to win .. mathematically a lot of votes in just a few cities ... will no longer win.
It is the candidate that achieves the wider distribution that will win.
For the next 20 years, this favors the conservative ... for the first time in 100 years