As I understand it, once the researchers came to this point, they basically said, "welp, we have no idea what changed but culture is different" and they're not wrong.

That's not how I read it - a fracking job, for example, will not make you an "elite" unless you already have the schooling and experience to go to management. It will provide you with a better income than you had before but notably, it isn't a stable income; the fracking fields of North Dakota are boom/bust dependent on where oil and natural gas prices are within the option cycle:

Similarly, fishing jobs up and down the coasts are lucrative but a long way from stable. I knew that community better than I know the frackers and it was a long damn way from family-friendly. In a way, the whole gig economy goes a long way towards demonstrating the erosion of stability in employment because once upon a time, if you were union and there was a slowdown, there were mechanisms in place to keep you from failing out of life.

I mean, the authors of your paper go as far as calling it the fracking "boom" and then comparing it to the Appalachian coal boom of the '70s, which was a lot less cyclical:

There's a lot more capital investment in getting coal out of the ground than there is in fracking (or there was, until mountaintop removal). You can almost watch them getting more efficient:

Nonetheless, there was a steady ten-year bankability there that simply doesn't exist with fracking. I don't know that the culture has changed. I do know that expecting your job to be there ten years from now is a very different feeling than wondering if you're going to be invited back next season. Been there, done that, got vested.

But I bring this up because latently racist upper-middle-class Trumpers who want a return to Leave it to Beaver will never get it, even if Trump brings back the coal jobs.

They don't want a return to Leave it to Beaver. They want a return to Amos and Andy.