>I wonder what it would be like to be born in a low-income community in the US where social mobility is difficult.

I fit that description.

In short, my personal, anecdotal experience says immigrants often place a greater value on education, recognize more viable options for success, are more supportive of each other and have less fear of stepping out of their comfort zone.

I saw no shortage of people hamstrung by each of those things growing up, particularly the de-valuing of education.