Why would you waste time to remake old movies when you can just create new material? There are an endless amounts of possibilities; I don't want to see movies that I have already seen. Give me NEW STUFF.
I don't know? Ask Disney and the rest of Hollywood. All they do is remakes now. It appears that's what people want and it pays the bills.
The biggest Disney movie of 2017 outside of Star Wars VIII is going to be a remake (Beauty and the Beast).