I'm going to take this argument in a direction to where it applies negatively and positively and has been raging since it's inception. Specifically MMO games.
The problem with it being that the carrot on the stick has always been 'more content', to which players answer with 'more time' or more importantly 'more money'. And if the creators of the MMO cannot keep that treadmill running, the money... goes bye bye.
The content has to be gated, or players have no reason to keep running on the treadmill. They don't see the 'other players' who've braved the vast golden gate and come out with shinier gear and fancier mounts, and then ask themselves the damning question; 'Why am I still playing?' And depending on the individual they'll likely stop before making those social ties.
Now reapplying this argument back to splatoon, it's a very different beast with significantly less content, I feel that formula has been trying to creep more and more into the online functionality of games like splatoon because it's how MMO's function and how they see all that money thrown their way without the developers stopping to ask themselves how and why that formula worked there. They're simply told about it and and to work it into their 'game plan' somewhere because it was a buzz phrase heard at a dev convention or some bullshit.
It would and could work if the content was vast and varied enough, but...as you said...five maps, it's not quite a juicy enough carrot.
Edit: My bottom line is as a concept it is not inherently wrong, it is however applied to the wrong type of game here.