Part of the "Episode IV" thing was to call back to the old serials Lucas was familiar with. And yes, he was so sure it was going to be a flop he took Spielberg up on his offer to exchange a % of the profits, in perpetuity, for a like % of the profits from Close Encounters of the Third Kind. I'm sure Stephen has been laughing at the bank every month ever since (although I think the deal might finally be kaput now that Lucas sold everything).