Carmack is a great programmer to be sure. Commander Keen, however, was not a better version of Mario. It was worse than Mario in every way -- art, music, and gameplay are all inferior.
Nobody outside of Gen X PC gamers know what Commander Keen is. Everyone knows what Mario is. While copying may be the way design works, copying only gets you so far.
Nobody outside of Gen X PC gamers know what Commander Keen is. Everyone knows what Mario is. While copying may be the way design works, copying only gets you so far.