I'm Gen X. I did a ton of pretty crappy jobs in my early 20's while I worked out what I wanted. Building site labouring, warehouse picking, farm work, retail work, you name it I did it. During that time, on the wages I earned from those jobs, I could afford to rent a (small and pretty crappy) place to live, eat 3 meals a day, maintain a car (though I ended up ditching it in favour of public transport) and have some money left over for entertainment.
I never needed to work multiple jobs, and while I was never able to take holidays or be extravagant, it was an OK life.
I was in the UK rather than the US, but I'm not sure that makes any difference.
When did we accept that life in your early 20's needed to be so hard?