Those jobs are often not easy to replace financially for the people working them. It involves uprooting their families, or being away for weeks at a time, working in the natural gas industry or similar, and they still don't make more than they were making in coal. I grew up around coal country Appalachia. Making $50,000 per year in a coal mine in the early 1990s, anywhere in Appalachia, was a financial godsend for those workers. I knew a lot of families that it provided a solid middle class life for, people that otherwise were going to be stuck working low wage jobs in those regions, if there were any jobs at all (and it was a hard, dirty, unhealthy, dangerous job; they all knew that).
A typical Sears worker has plenty of other opportunities at comparable or higher pay. There isn't a shortage of $13-$15 / hour jobs in the US, particularly in the locations where most Sears stores operated historically.