Impostor syndrome is pretty much universal (insomuch as it crosses class/economy boundaries) whereas what has been mentioned here is a sort of anti-entitlement very specific to people who grew up poor. People in this situation are often afraid to ask for what they are worth (to the point where they will sabotage their careers to some degree as noted in Gustomaximus post), are generally afraid of authority even when there is no reason to be or the authority isn't actually an authority over them, etc.
I've definitely seen and experienced this phenomenon myself speaking as someone who grew up fairly poor -- single-mom American poor (which, as all things are relative, is quite different than seriously-might-starve poor... at least for now).