While I can't stand Trump personally and many of the things he stands for, the fact is that the American left has enclosed itself in a small number of alpha cities (look at the county election map) and effectively written off the rest of the country.
The objective fact is that it is impossible for American industry to the American worker to compete with industry in countries with no EPA, no OSHA, no workers comp, no unions, an artificially low currency, and artificially depressed wages. This isn't about being globally "competitive." It's just not a fair fight. If this is the reality of globalization then it means the working class in developed nations is permanently relegated to poverty and dependence. The latter goes radically against these peoples' values. They don't want welfare. They want jobs.
Both liberals and old-guard conservatives have completely ignored this issue. Too many people are getting rich off labor arbitrage for one, but the more immediate reason is that it doesn't affect them very much. They tend to be urban, wealthy, and disconnected from the places and the people this issue does affect. Case in point: Orange County California (where I am sitting) is historically a Republican enclave but this year it went for Hillary. It's also very wealthy, educated, and fairly urban (and becoming more so). Meanwhile historically Democratic rural areas went Trump. You do the math.
You can't write off your entire working class and rural population in a democracy. This is the result.