I'm sure everyone working multiple jobs is not in this situation but I know people who don't need to work multiple jobs but do anyway. Hell, I've considered doing it myself and I make more than enough to support my family on one income. I'm working from home and the nature of my job has me sitting around waiting to answer questions fairly regularly. It would be pretty easy to land another remote gig and stack incomes with the goal of paying off my mortgage early. I haven't seriously pursued it yet but I might. You never know what the future holds. Having a paid off house changes your income needs in a major way.
The unofficial motto of polyamory is "Monogamy? In THIS economy?!?".
I've shared a home once with a partner and her girlfriend, but it didn't go well; my partner was a deadbeat and not only never found a job the entire 10 months I lived with her, she never even tried to find one as far as I can tell. She didn't even get child support from her kids' dad. Her girlfriend and I each worked full-time to support her and her kids with a roof, utilities, food, fucking doctor's visits...I had to pressure this woman into applying for food stamps ffs. I finally had had enough and told her to go move back in with her mother because I wasnt going to be paying for her any more. And then she and her girlfriend moved out together and got a place. Good riddance, and holy fuck was her girlfriend an enabler.
I'm not against sharing a home with partners and metamours again in the future, mind you. I just intend to get to know everyone a lot better than I did in that circumstance.