Or massive editorial interference.
Editorial Mandates can only do so much. The writing in Nisekoi is so utterly sheep-leading that there's no way it can't be deliberate.
"Oh it's going nowhere but at least it can't be worse"
"OH HEY I'M THE STUPID SISCON CHARACTER WHO ALSO WANTS TO JUMP THE BLAND PROTAG'S BLAND DICK FOR REASONS THAT ELUDE DOCTORATE LEVEL SCHOLARS.
OH AND THE PLOT YOU WANTED? WHOOPS I JUST KILLED IT! THE MAGUFFIN IS LITERATELY USELESS NOW!
LET'S RUN THIS STORY FOR FIVE MORE YEARS AND MURDER THE B TIER MANGA THAT COULD BE WORKED UP TO AN A SO I CAN STAY RUNNING FOREVER!
HIGH FIVE, KUBO AND KISIMOTO! I'D HIGH FIVE TOGASHI BUT HE DOESN'T FUCKING EVEN BOTHER TO SHOW UP TO THE OFFICE. HE'S USING JUMP AS A FUCKING DOLE CHECK! I SURE WANT TO BE LIKE THAT!"
That isn't the writing of a man press-ganged. That's the writing of a man vindictively playing the system that is itself willing to be played.