Why do they remake good movies?

Richard Attenborough
in Brighton Rock

Last night I watched the movie Brighton Rock, not the 1947 original movie staring Richard Attenborough, but the 2010 remake. I enjoyed it, but it still forced me to ask, "why do they always remake good movies?"  It's seems rather counter-intuitive to me. A director has made a film and its been a success, rave reviews, good ticket sales, and perhaps, over time, like the original Brighton Rock, it becomes a classic. So why would another director want to remake it, since they'd be fortunate to better the original?
    The obvious answers are:

1. because, like a Shakespeare play, it's a classic and everyone one wants to give the topic their spin.  But, that doesn't really apply - there aren't lots of remakes of Casablanca!
2. because its an easy way to make money - the original has high name recognition, a  warm glow, making it easier to raise production money; fill the remake with a great cast and you have an easy recipe for success.

Sadly, I think it's the second argument. But, I still wonder why directors don't prefer to remake a bad movie; after all, the previous director screwed up and they know they can do better. Therefore why not remake the bad movie into something better? Sadly again I think argument (2) comes into play - the original stunk so production money can't be raised.

Sam Riley
in Brighton Rock

   If you've not seen the original Brighton Rock, based on Graham Greene's novel, then see the new one. It's very good - a great noir environment set in seedy Brighton. I read the book at school and enjoyed it, but was much too immature to understand its dark themes. The movie does an excellent job and has a quality British cast: Helen Mirren, John Hurt, Andy Serkis (aka Gollum & King Kong), and Sam Riley, who is as good as he was in the excellent Control. If you loved the original movie, then watch the remake as well - you'll be irritated by scenes from the original constantly popping in to mind, but may enjoy how the modern version is able to deal with its dark themes in a stronger manner. Both movies have an excellent ending - one of the best in cinema (IMHO).