You are going to need to take that up with Wikipedia:
Common definitions for the middle class range from the middle fifth of individuals on a nation’s income ladder, to everyone but the poorest and wealthiest 20%.
That doesn’t say anything about blue collar or having a degree.
The trades are blue collar and can make more than a lot of lower paying white collar jobs. Hell, I just had a union blue collar job back in the day and had to be picky about which tech career path I took out of that because it paid as well as the lower end jobs I had been eyeing.
You are going to need to take that up with Wikipedia:
That doesn’t say anything about blue collar or having a degree.
The trades are blue collar and can make more than a lot of lower paying white collar jobs. Hell, I just had a union blue collar job back in the day and had to be picky about which tech career path I took out of that because it paid as well as the lower end jobs I had been eyeing.