On the one hand there's potential, but motivation is also important.  Gifted classes are a way to keep the slackers from holding back the kids who are actually trying.
  If there's a kid who's creating an atmosphere in which learning isn't cool, that kid needs to be shunted out of the way and kept out of the way until he smartens up.  You keep the door open as long as possible for these people, but success requires both opportunity and the will to succeed.