@matzesingt"The carrot is called a high rank"
Somebody once said, "That and a dime will get you a phone call." Dating myself there, I know.
The utility that I can see in a ranking system is to have it tell you where you stand relative to other players. That is one aspect of ranking systems that seems psychologically coherent to me. But in my experience most of the players I came across in ranked, or conversed with in forum environments, treated ranking systems like a ladder. And got incredibly frustrated and even angry when they hit their ceiling. They would vent this frustration liberally on the developers and also on their teammates or anyone within earshot. It's just depressing to see people so frustrated over something they completely misunderstand, or possibly understand too well but can't control or master. It's a rare player in my experience who enjoys the process of ranking up to the limit of their abilities and then feels no bitterness about that limit. Unless you're a player who is a household name. And therefore probably has no skill ceiling at all to be frustrated about.
All that said, more power to the people who genuinely love the grind.