I don’t know if there’s a term for this already. If not, I’ll make one.
I’ve read plenty of manga recently, and if you’ve read much manga, you know it’s long in general. Really, really long. Stories stretch out because they’re serialized in weekly or monthly magazines and it’s in the publishers’ and authors’ best interests to keep a popular story running for a long time. However, that’s not the only reason.
But wait. Before I go any further, be warned that everything I say from here on out is original research and is not the objective truth and yadda yadda blah blah blah.