As someone that barely ever reads any manga, no, you are not alone by a long shot.
I hate how the story are always left half finished, often times just as things are getting interesting.
seems like sequels that finish the story, for stuff that was started long ago rarely happens.
It's just so frustrating and annoying.
It would really be nice to know how it freaking ends, they should at least make up a ending if they don't plan on ever making a second season.
Instead we're forced to spend years slowly following the endless flow of manga chapters.
Maybe I'm not that interested in reading the manga/novels?
Sometimes the first season doesn't do well at first, so the anime producers drop it, even though it might develop fans latter who want to see how it ends, like airgear for example.
There's tons of anime that ends as soon as it really starts. like Aoi Hana for one, an anime which like many other is just a glorified advertisement for the manga.
Then there's manga that might gets canceled after a anime has been based on it's first few volumes, what happens then?
It's not like there aren't finished manga they can base stuff off of.
They just like to go with whatever is popular...