I don’t think humans would be naturally self centered if they lived in an environment that actually encouraged sharing and cooperation instead of actively encouraging and rewarding psychopathy and selfishness.
There were likely people who thought it impossible that wolves would someday become domesticated, and eventually be our best buds, due to their ‘unchangeable’ nature.
We are all products of our environment.
Humans are also inherently cooperative for survival, and it has been argued by some credible historians that our current forms of antagonistic society is an abberation from the norm.