20 million is a huge milestone! Not many unbundled software has reached this level of sales and no I don't consider a plastic steering wheel a hardware bundle. It's also amazing that most of the sales have been close to original retail price. It didn't rely on some $20 discount edition to reach these sales.
Anyone can guess. It takes no effort to throw out lots of predictions and have some of them be correct. You are not and wiser or better for having your guesses be right. Even a blind man can hit the bullseye.