SW would never have been finsihed without Fox. The shot footage would have been canned and lost forever. Lucas paid everything when it comes to ILM and kept the production afloat until Fox finallys tarted paying. Then they could finish the effects, edit and mix the film... and distribute... just as important.
Look, he paid for almost everything, especially the effects for almost two years. He had no income other than from American Graffiti. He fought his way through it all for two years, trying to get Fox to pay up. Which they didn't for a long time. If anyone is repsonsible for the success of SW it is Lucas, and Lucas alone.
So no matter what Lucas did to it before hand, if Fox hadn't have paid, then there might not have even been a Star Wars, or at least not a very good one.
But without LUcas there vever would have been a SW, it's to his own credit that it was made. Fox commited but wiated with the paperwork for a long long time.
And true, if they hadn't paid it would have been lost forever, but just a bag of money is not enough to make a classic.
In the end Fox didn't do much to help Lucas make his film apart from giving him money and fairly late. It's to Fox's Alan Ladd's credit that he believed in Lucas' idea, I'll give Fox that. But they weren't very supportive to Lucas and yet he gave them the biggest box office hit EVER! And that, fair is fair, is thanks to Lucas.
Lemme rephrase: they did less of an effort than most pictures they financed. I mean, the guy's in pre-production and production for two years before they start paying up and signing contracts.... liek about 6 months prior to release.... Yes, they paid, without Fox it would never have been finished... but filmmaking is more than just handing out money. When it comes down to the other thing besides money it was all Lucas.
Honestly I have to agree with Queeq there. Of course Fox gave Lucas the money but that was that basically. I think it was more or less Lucas' drive to make the movie a reality more than it was fox giving him the money.