I couldn't disagree more. Most people I know work so much because either 1) they have a very high paying but high demanding job or 2) they overconsume and have to make the money to pay off the debt that they've created with their overconsumption.
For the former (my friends at Google, well-funded startups, and in finance, etc.) I'm afraid I'm not going to shed any tears for them.
For the latter, most people I know are neck deep in auto loans, mortgages, credit card debt, etc. Up until this year, I would be hard-pressed to name a friend who had a car that was older than mine. My group of friends roundly poked fun at me when I furnished my new apartment with nice craigslist furniture.
To address your point directly, for most people, finding a cheaper apartment is an alternative to "moving back in with parents".
I'm currently living in a 450 ft.² studio apartment in a small town in Tennessee for $400/month. I'm quite sure this is affordable to anyone who isn't making minimum wage, and probably them too. Making minimum wage? Get a roommate. I've had roommates my whole life.
No, people choose to work a lot because they're living a lifestyle that is more than they can afford.