Well, the whole remake thing comes from the fact that while the movie industry on the whole has always been conservative (hence distinct generas and film types), now it's gone uber-conversative. Execs are always, always pining for the next big thing, the blockbuster, the one that'll make them a lot of money. And to conservative minds, known qualities and safe bests are always more appealing than the risk of origionality and innovation. The fact that so much constant emphesis is placed on the bottom line of a movie by both the industry and the viewing public means that those with the money to back movies are less inclined to gamble with it. Remakes have a built in audience factor that cannot be discounted. A good number of fans will attend any remake just to see how badly it butchered the original, and that's good enough for some execs.
As for their remake of the Cronenberg version of the fly... yeech. That's just sad and tacky.