Trump is grabbing votes from the labor faction more than any past Republican candidate -- his stance clearly taps into the American psyche, that American exceptionalism is real and that every American company should put American workers first. Jobs, jobs, jobs! is a great platform to run on.
Increasing net welfare of the planet by globalizing as fast as possible would undeniably end in failure as the resources would not at all be redistributed evenly, as can currently be seen as plain as day. Globalization is a threat to everybody as it increases instability across the board except for the very wealthy.
There is value in retreating to isolationism.