Wouldn't you use Star Wars as a money making machine if numerous companies depended on the brand to survive? Sure, Lucas' companies do have other sources of income, but not as much as when Star Wars is front and center.
And the notion that he scarfices his art for money is subjective considering differences of opinion when it comes to the Prequels, which is what this thread, again, is all about....the opinions of the Prequels...