Given that, it is not unreasonable to wonder (hope?) that there might be human living conditions that reduce "brutally dominant social heirarchy".
The best part is: we even appear to have archeological evidence that this is true, for humans!
IME the theory is a reactionary (i.e., anti-liberal, anti-humanitarian, anti-human rights) myth to justify the rule and worship of power.
It's probably more viscerally visible in poorer parts of the world, though trying to compare which is worse, is not very clear. You could argue in the western countries it's easier for someone to become entrenched and cement a position of "top dog" while if you are in a tribe in Africa the position is more fluid and volatile.
I think using the term 'brutally dominant' I invoked images of violence, and maybe something like 'cut-throat' is (ironically) more apt. While you yourself may be in a good and comfortable position, it doesn't negate the reality that people vie for positions of power all over the world every day and have for the entirety of history. We are not just Bonobos living in a forest.
if you mean literal brutality, but how the uber wealthy treating those of lower wealth could be considered brutal as well--in modern parlance of course.