I come from a very poor upbringing myself
@mapman , though myself and my siblings have all done very well for ourselves. We do have our parents good genetics, and good worth ethic to thank and a loving upbringing. We were never pushed, but we were never told there were limits either. I would not call myself or my siblings overall very humble and my brothers and I definitely not, but we certainly don't look down on those of lesser success and we don't equate wealth with being a better person (or worse). It has made us all more fiscally right wing, but we are all socially pretty left wing, but politically right in the center.
The origins of humility as a "virtue" are not necessarily good though. It can be traced by to religious piety and one could even say subservience (to a diety).
Nietzsche even characterized it as a defence mechanism for the weak to survive the strong (paraphrasing). By calling it a virtue, we are "forced" to assume it is a good thing without reflection on whether it is or not.
Being exceptionally aware of your limitations and failings does not require one to be humble.