Also, you always eventually reach the end of a book. In which case you have to take a break to find a new one, which you may or may not like as much.

This applies to basically every form of media prior to the internet—movies, TV shows, music albums, etc.

I personally prefer games that are one-and-done too, and this is partly why. I want to immerse myself in a virtual world for a little while and then move on with my life and/or find a brand new virtual world; I'm not looking for an endless rabbit hole.