It would have never succeeded because the characters aren't lovable (IMO). Though the story is great in the OT, and the effects knocked our socks off, Luke, Leia, and Han were three of the ultimate good guys to root for, and Darth Vader was ultimate bad guy to hate (or love). The Prequels, especially TPM, had none of the above. How could fall in love with QuiGon or an underused Kenobi, or a montone Padme, or Jar Jar? Or think Darth Maul was great when he was only in it for 5 minutes?

Characters, characters, characters, Lucas missed the boat on that one in the PT.