It doesn't matter in any case what Greer's interpretation is, because it is clear from the testimony of the women attacked by Weinstein that even if some of the incidents could (if one squinted through half-closed eyes) be dismissed as a simple trade of sex for a film part, many more were straightforwardly and unequivocally sexual assault.
As for the "why didn't she just leave?" questions, I've been pondering this in connection with the Ansari case. I don't know what happened on that "bad date", but I do know that probably the bravest thing involved walking out. I want to explain why it's so hard to do - not just hard, absolutely fucking terrifying. In my case, I'd found myself alone in a room with a man who wanted to have sex with me (having invited me there on the purely platonic pretext of offering me a cup of tea). He had positioned himself between me and the door. He had stressed that it was a lovely quiet bit of the building with no-one within earshot. I had to get up and walk past him not knowing whether I would be raped. I made a split second judgement call that this particular man would not escalate to physical violence if he couldn't coerce me verbally, and it turned out I'd made the right call. But it was still fucking terrifying, and it was luck rather than judgement that I got away unscathed - rapists do not come with the mark of Cain tattooed on their foreheads.
Some women in the same situation subconsciously decide to acquiesce because then they still have the psychological defence mechanism of "it was just bad sex" open to them. Getting up to walk out makes it unequivocally rape, and you have to deal with the aftermath of it. I have every sympathy with a woman who can't find it in herself to take the chance on walking out.