I think the x axis should be rather interpreted as "learning progress" instead of absolute time - then it makes more sense. But ofcourse when read like that it

I think the x axis should be rather interpreted as "learning progress" instead of absolute time - then it makes more sense. But ofcourse when read like that it lacks the absolute time reference (notepad can be learned in a day whereas vi takes months) and generally yes, this is just a tongue-in-cheek sketch. - Still, not too far from reality, imo.