That's a whole different concept .
Try this :
You're in college and you're half way thru a major and realize that you don't like it. What do you do ? Drop it and start a new one , because there is no point of investing time in something you don't enjoy .
Many people might hate middle school, But dropping out in the middle can be a problem.
Yeah, this can go on forever, but the initial concept and the focal point remains, both process are time wasting, and literally time consuming. Rather watch a story to it's end, rather then to just drop it, especially something which most people have been reading for years. You can simultanously read two books, or more, without thrashing the ones you are previously reading. Obviously something which has come to an end, almost tho.
This is rather more prominent in serials or something which is published weekly, the author can go about with, which in retrun amounts to criticism. So that cannot stop, sadly.