Because compared to most attempts at adapting books, LotR did a good job. The changes were made to make the trilogy easier to watch since the books can be a lit

Because compared to most attempts at adapting books, LotR did a good job. The changes were made to make the trilogy easier to watch since the books can be a little difficult at times, or to make the characters more dynamic. They weren't perfect, but no adaptation is. As for the Hobbit, I agree with you. That entire trilogy was a mistake. Personally, while I loved the LotR movies, I also feel like they were the worst thing to happen to the books. Ever since the movies came out every studio has wanted a piece of it for nostalgias sake. I remember when the first two Narnia movies came out I was sad that not as many people liked it since I love Lewis every bit as much as Tolkien, and I wanted my enjoyment of the books to spread. Prince Caspian had inaccuracy problems, but the core story was there. After the abomination that was 2010s Dawn Treader, and seeing how corporatized Middle Earth has become, that seems like a mercy in hindsight.