Can we cancel her forever but keep HP around?
Abso-fucking-lutely.
Rowling but be an awful human, but as a teacher I still think the series itself is an incredible tool. At 7 books it's a pretty lengthy series, but it's also easy enough for most kids to jump into. The books grow with the reader, so Sorceror's Stone is going to thematically be less intense than, say, Order of the Phoenix. After the first 2 books, it's also not really stand alone. You need to read Year 4 before you can read Year 5, etc.
It sounds like it shouldn't be a big deal, but when you take into consideration similar books in that
Lexile level, there really isn't anything to compare it to. Harry Potter is unique in that the books are big (literally, it's chunky), but also it's a book series where you can stick with the characters and continue their adventures. The more time you spend reading them, the better the payoff is going to be. Because the books are so big for that level, I've found that it's an absolutely incredible confidence builder. For many of my students, the series is the first "big" books that they get into.