Not promotable to manager but seen newly grad promoted sooner.

I've had it with corporate America. I quit my old company of 20 years. Despite stellar reviews year over year, I couldn't get a manager position. I managed a program, the only SME too. Then I just saw my old intern 3 years ago posting in LinkedIn today that he just got a job from my old company as a Manager!!! 3 years in the workforce, 3 different companies, and came back to be a manager?? Never again will I be loyal to one company!!! I should have job hop many years ago. I'm pissed