Should've expected that ending based on the title, though that said, I did absolutely predict the old man's motivation. He wants to permanently alter the gene pool by making himself the only man so every woman will want him. Sadly for him, he's never read that other manga (1:39), so he doesn't realize just how terrifying an existence that would be.
All that said, why didn't the mind-reading girl pick up on what he was planning? She's been shown capable of reading his mind before.