Being a hired employee in a great-paying job - which I am - is actually the hallmark of the middle class. You can argue about what strata of the middle class you are in. Lower, Upper, Really Upper. I've-got-three-commas-because-I-was-employee-235-at-Google Upper. Whatever. You're still a hired hand, and you are middle class.
I disagree strongly. There comes a point in the life of a few lucky people when they
choose to work because they want to, not because they have to. Employees with all those commas fit that description perfectly. If they stay at their jobs, it's not because they need that paycheck to pay the mortgage next month. It's because working is more fun than not working at the moment. They might decide next month to try their hands at [insert self-funded project name], or they might not. This freedom makes them very much NOT in the middle class.
Looking like something doesn't make it so.
The Wikipedia article on "middle class" says this:
The size of the middle class depends on how it is defined, whether by education, wealth, environment of upbringing, social network, manners or values, etc. These are all related, but are far from deterministically dependent. The following factors are often ascribed in modern usage to a "middle class":[by whom?]
Achievement of tertiary education.
Holding professional qualifications, including academics, lawyers, chartered engineers, politicians, and doctors, regardless of leisure or wealth.
Belief in bourgeois values, such as high rates of house ownership, delayed gratification, and jobs which are perceived to be secure.
Lifestyle. In the United Kingdom, social status has historically been linked less directly to wealth than in the United States,[4] and has also been judged by signifiers such as accent, manners, place of education, occupation, and the class of a person's family, circle of friends and acquaintances.[5][6]
Cultural identification. Often in the United States, the middle class are the most eager participants in pop culture whereas the reverse is true in Britain.[7] The second generation of new immigrants will often enthusiastically forsake their traditional folk culture as a sign of having arrived in the middle class.
If you accept this description, one can have a high income but still be middle class. An important respect in which many upper income people are middle class is that they expect their children to have independent careers rather than just living off of inherited wealth or managing a family business.