> "The thing about trades is you don't need to be smart- just hard working."
Have you ever worked a trades job? It takes "smarts" to be a good HVAC technician...it involves knowing and understanding practical thermodynamics, electricity, and mechanics.
Due to the evolving nature of the equipment that mechanical and electrical technicians work on, they now have to know how the equipment works, how its networked, and how to troubleshoot any problem involving the equipment. It isn't uncommon, at least in the industry I work in, to find technicians that have extensive knowledge of electronics, electrical/mechanical equipment, and even have their CCNA and good networking/system administration knowledge.
There are some skilled trades that companies, even during a recession, can't get around...fire alarm/suppression system inspectors/technicians, elevator inspectors/technicians, electricians, electrical code specialists, OSHA compliance specialists, etc...
Keep in mind that that is your average journeyman's pay. You'll have additional incentives depending on your workplace, role, and experience. For example a utility company substation technician will make journeyman's pay + extra substation pay, a substation foreman will also get additional pay, a licensed master electrician will earn even more, etc...there are definitely high paying "blue collar" jobs in the utilities industry.
It depends, as a technician I was active, mobile, exercised my muscles daily, and was in very good shape. After I got my CS degree, I spent the next year sitting in front of a desk staring at an editor and couldn't stand it. I moved back into the trades and it seemed like the healthier (and better paying) option.
In many cases, you'll end up making something that works using simple relays way more complex, so you'll still need some kind of technician to troubleshoot the equipment when it fails. The "advances" in equipment technology is mostly for sales brochures but in many cases the increased complexity creates more failure points and simply requires a different type of technician to troubleshoot.
This is more in the compliance sector, but I get what you're trying to get at.