@Protein
Like everywhere, it depends on the school he works at, if he works in a cram school he can make some bank, if he gets in a private academy he would not only make bank, but get prestige, if he works in a public school.... well thats like throwing darts.
Being a teacher in Japan isn't exactly the best paying job ever, but it's not nearly as unlivable as being a teacher in America, where you literally can't make a living and also no one appreciates you.
But yeah, this is giving very Nariyuki vibes (from ぼくたちは勉強ができない / We Can't Study / We Never Learn (the "official" english title, which is a bad translation on viz's part))
After reading 208 chapters, I'm not sure if the publisher of this manga even gives a hoot about progress. I lost track of the last time any real progress has been made. Last "progress" was more like a half step up, a half step down. Dwelling on graduating and Tokyo U is keeping this from making proper movement.
@cillbosby: Manabu hasn't had her as a motivator in ages. Even when he ran into her on their separate visits to Tokio U, he was only vaguely surprised to see her, not at all flustered or even particularly intrigued by her presence.