Why Make a Book Series Like a TV Show?

Due to an unfortunate spasm of boredom that severely sprained the dignity of several cortices of my brain yesterday, I won't be continuing the series about Adam and Eve. To be entirely honest, I'm not sure why I started it. Ah well. My apologies.

Different Dialects

When a director makes a movie based off of a book, there are always changes made to the story. This is because of one or more of several reasons:

1) Movies and books are fundamentally different formats, and so have to be done in different ways.
2) Two hours isn't enough time to do everything in the book.
3) Whoever was in charge of the movie clearly only read a description of the book and then used the other reasons as excuses for their shoddy work (I'm looking at YOU, makers of Ella Enchanted. *glares*).