Honestly, it doesn't make a whole lot of sense to me why anyone on that ship would get promoted. There's nowhere to go. No one is leaving that ship for a very, very long time. If you kept giving promotions to everyone who deserved it*, how many years would it take until it was a ship crewed almost entirely by Lt. Commanders?**
Yep, someone has to do the grunt work.
Who do you order to do the grunt work if everyone is of equal rank?
This whole conversation has been about Harry Kim, a senior staff bridge officer and department head. He is not a grunt. Shouldn't he maybe outrank the grunts in order to set himself apart as a senior officer on the ship? I'm not try trying to argue with you but at some point logic should take over.