Underrated point. *If* Lucas really wanted it done his way, nothing was stopping him from finishing 7, 8 and 9 himself. I think he passed the buck to Disney because Lucas is done with fan backlash. That's the impression I get from his recent interviews.
The difference being that Roddenbery's death allowed his creation to really take off and soar (Late TNG and DS9). What we have here is another situation entirely, The Creator still lives! With the timing of Roddenbery' passing, DS9 and the shows that followed were no longer beholden to the desires of The Creator. These points are well established in the HBO doc "Chaos on the Bridge."
Repeating myself here, but I feel it's important to re-iterate that "betrayed" is Bob Iger's word going into Lucas's mouth. Lucas may feel betrayed, but he didn't say it.