Agreed; I'm originally from the Netherlands myself, and the situation there is the same as in Germany. Over here in the US, it's a different story. If you live in a rural area (like I do) you really need a car, because there is no public transportation anywhere around.
Depends on the city and the job imo. Many cities have very bad late-night bus services (often non-existent), which is a problem if you're a janitor or fast-food worker who gets off at 2am. And many of the better-paying jobs available to the poor are in wealthy suburban areas with bad bus services as well, so with no car you're cutting out a bunch of employment options, like cleaning houses or waiting tables in upscale suburbs. Atlanta has interesting rush-hour traffic along those lines, with a large group of poor people from southern Atlanta driving to jobs in the suburban/exurban counties to the north.