That is why politicians love to use the term “middle-class” and never define it. Just about everyone who has a job thinks they are talking to them. Everyone from the carper cleaner to the doctor will say they are middle-class.
The original definition of middle class had it consisting of doctors, lawyers, business owners, etc -- people who worked for themselves.
If you worked for a paycheck, you were "working class", even if the paycheck was significant.
Traditionally, upper-class people were able to live well on just investment income, and you were not considered upper-class unless you had one or more full-time, live-in servants.