I would still try to fight for more than you make. It will be tough, don't get me wrong, but I think most industries are in this position one way or another. Everything is going up, and everyone has to eat. Why can't everyone make more, so less people suffer? The costs for everyone have certainly increased. A lot of these "record profits" should really be finding their way to employees, but they rarely do anymore.
With the "unskilled coal mine work" example specifically, I believe a big reason for their pay rate is the numerous immediate and long term health risks that are associated with it. Historically, mining has been a pretty fatal/dangerous job. They miners will probably need that money down the road if they get any of those bad conditions. It's certainly not a job that I would feel safe doing, nor is it one I would ever do for cheap. You should look into all of the associated lung diseases and ths effects that certain mined materials can have on the human body, especially with prolonged exposure. PPE can only do so much sometimes.
When I see people making more than me with less skill, I think "damn, I should be making that too". Why can't both jobs have good pay rates? Both would be nice. What a world we live in.
If you can, unionizing might help. It takes the company perspective from "we'll lose one great guy" to "holy shit, everything will crash and burn if we don't meet their demands!". I would also look into the laws in your area. Where I live, unions can protect you well before you actually create a contract. That knowledge was very useful to my coworkers and I a couple of years ago, because we previously thought that they could just fire us for trying to join a union (jobs are at-will here).
If you get a good union, the pros can outweigh the fees easily. They can cut right through a LOT of corporate bs, and they will usually provide lawyers for you if your company tries to screw you over. The lawyers mine provides are pretty top-tier.