Because it's Hollywood greed at it's best. The source material was a fun book, but it doesn't warrant a 5-part movie saga. Jk Rowling can't write scripts. The story contains two very distinct plotlines that don't mesh at all. It's full of moments that don't make sense in-universe like the immediate excecution by black goo (the US doesn't have a judicial system?). The main enemy is so incredibly powerfull he makes voldemort (who is said to be the most powerful wizard who ever lived) look weak. Why didn't we hear about this amazing, incredible world-ending magic in the first 7 movies/books? Because those books where actually carefully thought trough, unlike this movie script. Besides that, the story was full of very convenient, ex-machina moments like the eagle shit at the end. Sure, it looks cool but if the movie doesn't make sense I'm not invested in it. Furthermore, the acting in this movie is pretty damn bad. Eddy Redmayne is an amazing actor (see; the danish girl) but his acting is so dull and shitty in this movie. I doubt it's his fault because all actors seem to suffer from the same 'let's awkwardly mumble our lines to look quirky' syndrome so I'm blaming it on the director. Also, Johnny fucking Depp, holy shit I don't think ive seen a worse casting decision the past 5 years. Any Excitement about Grinewald gone in a second. Why didn't they keep Colin Farell? He and Ezra Miller were the only redeeming factors this movie had going for it. In the end, this is - just like the hobbit- a fun story stretched out into a ton of shitty movies because of money. I'm a big fan of the original HP movies and books, this movie honestly makes me like the established universe so much less.