Why so many sci-fi movie remakes? It’s the money, stupid.

Hollywood's obsession with remakes has always annoyed me. Author and critic John Scalzi explains the economics behind the ongoing trend which is seeing movies getting remade even more quickly than before.
For example, Paul Verhoeven's science fiction ouevre is getting remade. That includes new versions of Robocop, Starship Troopers and Total Recall.
Speaking of Total Recall, did you ever listen to Arnold Schwarzenegger's commentary track for that movie? It's the reason why I don't ever bother listening to them. It consists of Arnie describing what he's doing on the screen which is fine if you are blind, but useless for anyone watching the movie.
Have you ever considered that the Lord of the Rings movie is a remake? No, I'm not talking about the Ralph Bakshi animated version from the 70s, I mean the 1944 version that starred Humphrey Bogart as Frodo. What do you mean, you've never heard of it?