At our country's founding, 98 percent of Americans were agriculture workers. They lived on a subsistence level, barely able to feed themselves.
Today, only 2 percent of Americans are in agriculture and we are feeding the world.
Imagine how stupid/evil a politician would sound if he promised, "I'm going to bring back all those lost farming jobs!" Imagine how ignorant and gullible the voters would have to be to fall for that idiocy.
Just so with assholes who claim, "I'm going to bring back all those lost coal and manufacturing jobs!" And the people who fall for that are ignorant and gullible.
There are a lot less manufacturing jobs thanks to technology, yet we are making more stuff than ever before. The credulous rubes don't even know that we are making more stuff than ever.
We are doing a shitty job of preparing our kids for the jobs of tomorrow.
Take a look at these two photos. The first is from a car manufacturing plant in the 1970s. The second is a current plant. Take note of the number of workers in each.
See if you can find the humans: