imperialscum said:
Well he could simply get some other people to write and direct and just take the profit while sipping beer on the beach. Obviously there was some personal reason that he invested his time in it.

I think an overwhelming factor was toy sales and marketing. I mean, just look at the insane marketing campaign for TPM- one that was only matched recently by the ludicrous TFA campaign. He stated in the Leonard Maltin interviews in 95 that he was planning on only directing Episode I, then handing off II and III to new directors. I think this was still the plan up until the release of TPM, but due to its poor reception, he didn’t want anyone else to make a Star Wars movie that was significantly better than how own. Mind you, this is only speculation, but I think it’s both ego and profits involved, more than a want to tell great stories.