That is…unfortunately, exactly the opposite of what happens more often than not.
More often than not - promotions are accrued through social credit and personal preference.
You will quite often see the hardest working people get passed by for a promotion for the manager’s friend, etc.
Your ‘objective observation’ is…not accurate.
If this was the way it was - we wouldn’t need laws related to racism, sexism, etc in hiring practices.
I don’t know what kind of idealistic fantasy America you’re imagining up, but in the real one that exists on Earth these are serious problems.