The thing with part time jobs is that they are very few and far between and often unstable. It’s for companies that don’t need a full time person to do some menial task. It’s mostly intended as a “side job” like Uber/Lyft to complement your full time job and work a little harder to make some extra money while you are young, so it often doesn’t have the same benefits and protections, especially outside the US.
As others have said, most of the “millions now living” from the cover of that magazine have already died and if you were a child like me when that magazine was published, you’re now having children of your own entering the workforce and maybe you even have grandchildren. If I had done that, worked part time for all these years, I couldn’t afford kids, I couldn’t afford a house, I couldn’t afford savings for pensions, I wouldn’t have learned on the job as I have. Keep em poor and stupid.