I'm not sure poverty motivates very many. A car is enough of a priority for most who're over college age, and a lousy used car can be had awfully cheap.

A large fraction of those who lose their licenses via DUI just drive illegally, so the ones who are biking, even badly, are relatively OK in my book.

Since this thread doesn't seem contentious enough ...
I am familiar with the sort of cyclist you describe and based on my observations of the ones around here (Colorado), I think they mostly can't get licenses or register cars because they're illegal immigrants. So they're OK in my book because anyone choosing to live here as an illegal immigrant almost has to be doing it for commendable reasons.

Well, OK, actually it's just that riding a bike instead of driving carries a lot of weight with me. I'm not coming up with what exactly you could do on a bike that would make me think I'd prefer you were in a car. Sure, I get annoyed at bad cyclists; but they're a lot better than bad drivers.