trade school instead of a bachelor's degree

[sanantone]

we all know the limits of using the mean / average.  It isn't the whole picture.  Still, unless you're very specific or specialized, you have to look at numbers in a general sense.  Salary is one, but not the only factor of course.  Buying a house requires SO MUCH MONEY in some places, like Danika said, you have to really be a high earner to do it.
I'll give you another thing to consider, work hours.  If someone earns $50k and works 40 hours, that is an entirely different kind of job than someone who can make $50k working 20 hours - or even 70 hours. It's not just about the salary.  In addition, is there upward mobility?  As an example, my oldest son's first full-time job was at a warehouse where everyone makes $20-25 an hour - literally.  But that's it, there is no "up" so after a few years, people leave because it's a hard job and there is nothing else to do. No promotion, no prospect of a better quality of life.  So, it's a team of young men who can physically run their butts off and want money to buy a fast car and beer.  It's not a career and it's not a skilled trade- so outside of that one company, it's nearly impossible to walk into a different warehouse and earn that kind of cash.

I think plumbers make enough to have a middle class lifestyle in most places in the U.S., but they aren't upper middle class. There's usually a handful of companies dominating the local market, and the owners of those companies are the ones making six or seven figures. 

I think people need to look more at individual occupations than groups of related occupations. For the most part, plumbers and electricians make good money, but auto mechanics do not. It's also easier to be successfully self-employed as a plumber than as an auto mechanic because plumbers don't need to operate an expensive, standing shop. There's a lot of competition in the auto repair industry, and most of the small businesses will fail. 

In my last job, I learned that there are thousands of sole proprietors, partnerships, and small corporations that can't pay their taxes in Texas, alone. A lot of them also had no taxes to pay because they had no business, and they would ask us to end their sales and use tax permits.