If the MC had some personal problem he focused on fixing while leaving this "development" of the study group in the background, I think the pacing would fix itself. For example, where the f**k are their parents? In this situation, I would think it would be the parents that put the most pressure on them to fix their grades. I feel like I would have been 100% disowned if I repeated a year. Or at least sent to the doctor to search for some disability.
Alright, that's the problem. The author isn't threatening their living situations at all with this "repeat the year" thing. They're just doing whatever they want with no consequences and no hints as to why there are no consequences.