Did he need 200FPS? If you get the DVD and listen to the director's commentary you'll see that digitial will never be able to do certain kinds of shots. Hughes had shots running at 72FPS to 200FPS. Not possible with digital right now and yes it was needed - 60FPS wouldn't cut it. No current HD cam does 60 FPS or higher progressive frames anyway. For regular shooting it's great and can replace film. It's also easier to shoot dark locations or night scenes with digital as film requires lighting in order to expose the scene to film. Will digital replace film? In Collateral they used a combination of three cameras - two digital, one film, all because of the limitations of digital in shooting some scenes.

No doubt HD could replace film completely, just not yet. It will take another generation and even higher resolution than 1080P to do that, and of course more in camera control over frame rates, emulated exposure times (if that's possible), etc. Doing all of that in post-production isn't as nearly as convenient as doing it in camera.