Would you like to hear from a contractor who didn't have a degree and wasn't doing IT or some other kind of cerebral work?
I was a painting contractor for several years. I made 50K a couple years, usually more like 40K. This is going back 15-20 years.
Starting out I'd make about 15K-20K, the first year or two. Had to supplement with a night job.
The first step, whether it's painting, carpentry, plumbing, whatever, is to learn your craft. I was fortunate to learn from my brother who had been through the union apprenticeship program. People think there is nothing to painting, but there is, and you have to learn it primarily by doing it.
You work for someone else for a while, learn and practice your craft, accumulate the necessary equipment, then go out on your own. Then you work and work and work. I was putting in 70 hours a week and thinking about killing myself (literally). Then you start to ask yourself what jobs really make money and what jobs are really just using up your time? You don't have to provide a service to everyone who asks and do everything in your field. I started by offering any and all painting and wallpaper services. I painted new homes (as many as 20 a year working alone), repaint jobs, wallpaper jobs, wallpaper stripping, faux finishes -you name it, I did it.
I was doing different things everyday but the profit margins varied wildly. I started to focus on what I could do profitably and leave the other stuff for someone else. What's profitable varies depending on the individual (how good you are at one thing vs another thing) how many employees you have (I usually had none to 1 or 2 being paid under the table) what kind of equipment you have, Since I had learned my craft well, I found that I could paint for the carriage trade and get paid reasonably well. At the end I was doing only high end repaint work in the "posh" neighborhoods. I would still get calls from home builders and I would politely say no thanks; new homes aren't for the small contractor with few or no employees. Ironically I found I could also make money at the relatively low end of the market - rental units. Not apartments, but houses that a LL rented out. The LL would want the cost low, but quality higher than the typical apartment painter. Since I'm very fast I could make money here as well.
Most of the building trades, but painting especially, is boom/bust. You have to work long and hard in the summer because come February there isn't going to be any work. (In Michigan)
If you have capital you can employ others at much less than the value of their product and make money that way. But I never had the capital for several employees and a couple vans. It's a tough balancing act when you have employees, if they can't move fast enough you can't make money, no matter how low you pay them. If you get someone who can move you have to pay them well enough that there isn't a lot of profit. IMO you can make profit on volume with good well paid employees, or you can just go it alone and not have the hassle of being an employer.
So in short, I made $50K as a painter, by working my *ss off for several years, then settled into mostly carriage trade work. But I still had no pension or health insurance, sick days, etc. I had to carry a liability policy, which is a deductible business expense, but is still an expense that has to be paid.
Finally I came to my senses and got a $30,000 a year job with a pension and health insurance and a 40 hour work week, and a steady paycheck. I hope and pray I never have to make my livelihood as a contractor ever again.
I do feel fortunate to have a trade to fall back on. If it became necessary I could go back to it, and it's a very real possibility for an occasional "extra money" job when I retire, as long as I don't have to do it too often.
All in all, with the exception of a couple plumbers and maybe one electrician, I don't know many contractors who are having a very good life, even if they do make $50K a year.