If you haven’t read it (but something tells me you might have) read Thomas Sowell’s excellent book “Basic Economics: A Citizen’s Guide to The Economy”.
He talks about the concept at length of the dynamics of how people move through jobs and economic classes throughout their life.
He explains how people, politicians and analysts talk about poverty/low income earners as if it is a bucket you go into, and stay in for the rest of your life...in actuality, MOST of us make journeys through that level, but people who are motivated do not stay there.
Have read Basic and also his Appplied Econ and every other of his books...taught my kids out of the Uncle Eric series, and econ is my hobby.
You have to go about three minutes in to get to it...it’s great!!!!