Correct me if I'm wrong and I'm sure you will, but wasn't/isn't the franchise a nine movie idea/deal anyway? I thought I read that a million years ago, so I'd assume the basis of 7,8 & 9 are already in the can?
Aside from that, smart move on Lucas' part. Fudge, 4 billion bucks is huge and as he quoted above, might as well cash in and blow $$$$$ before your gone.