I'm fairly certain that the version Apple includes in Quicktime has not changed. Apple licensed the technology from Supermac, the makers of VideoSpigot capture cards. I guess Supermac was aquired by Radius, which subsequently went out of business. At some point CTI must have purchased the rights to Cinepak, either from Supermac or Radius. About seven years ago, I tested the CinepakPro Toolkit (the only way to use the CinepakPro codec), but I wasn't too impressed. I thought that MovieCleaner (now Cleaner) had better features.
Furthermore, the sample videos are not even appropriate for Cinepak. Cinepak, like JPEG, works best for photographic content.