In general I agree with your points but you miss a few big ones.
Ignoring the “great sleeping mass” and pretending that the U.S. consisted of the blue urban bubbles of NYC, CHI, SFO, and SEA is one reason Trump won.
What the left needs is new ideas, they have been selling the same ideas for 50 years, and when they get elected despite the rhetoric things for the “great sleeping mass” get worse. This is another reason Trump won.
The left has used the same attacks on the opposition for 50 years. After a while they only carry weight with the young who are ignorant of history. This is another reason Trump won. This is also why despite the constant barrage from the left, his approval rating is still around 50%.
A political party is about specific policy not high minded ideals. What specific policies does the left have today? Very few… except that they want to be back in power.