What is it with new Hollywood movies re-using the scores/themes from movies that are only a decade old?

Take Babylon AD. It uses the violin score from "Requiem for a Dream."

And The Watchmen is even more blatant. They are using Smashing Pumpkins "The Beginning is the End is the Beginning" which is off the Batman and Robin soundtrack and is a reworking of the theme song from that movie.

Don't get me wrong, I always enjoyed "The Beginning is the End..." more so than "The End is the Beginning..." but come one Hollywood, lets get original!