Another friend with a strong public school degree who floated around for months interviewing until she moved back with her parents, then finally got a job at the local library.
In your first example you mentioned a 'she'. From what I've been told from friends in the service industry, that's a plus (even somewhat if you're not considered attractive, but obviously much less so).
In your second example it didn't last, so it's quite possible a number of these "didn't last" experiences lead to doing deliveroo-style work.
Furthermore, I've been shocked by how terrible some people are at 1) considering alternatives to whatever choices they think they have, and 2) doing okay in an interview.
I get the impression lots of people are just not rational actors in these matters, and there are all sorts of hidden factors that can prevent someone from going for the 'better' jobs. I don't have strong opinions on what we should conclude from that, but I am at least inclined to think making the shittiest option as good as possible might be an all-round good thing to pursue.
A former coworker had a similar story. He got into a fight with his wife because she was spending all day in facebook instead of finding a job, so out of frustration and spite he went out to pretty much the first pizza joint he could find and talked to the manager. 30 mins later she now had a job.
Heck, I have another cousin with schizophrenia who managed to land a security job (he didn't last unfortunately due to his condition worsening), but it goes to show finding a low pay job isn't some insurmountable task.