Sorry to start a new thread on this, but been readin’ a few others and haven’t found this yet.
The reason Max does not go with Jackie is because he sees clearly, in the words and manner of her offer, that she doesn’t love him. It’s a beautiful and sad movie scene, and I don’t think QT tops it anywhere in terms of emotional depth. Watch the move again, from the moment he meets her he is trying to figure out if he has a chance; he doesn’t quite get it throughout the caper (but goes along with her because he loves her); gets it in that last scene. She doesn’t love him; but he would have done it all over again, because he loves her–which is why he did it in the first place.