Unless you're claiming that everyone making $300,000 a year could retire immediately, then of course they need a paycheck to live. Maybe you're thinking about the phrase "living paycheck-to-paycheck" which has a different connotation.

Contrast this with a person with many millions or billions in wealth. That person literally does not ever need another paycheck to live. In other words, they do not need to work to live, unlike a typical worker making wages.