The problem is (from my, or maybe also a dev's point of view) if you ever enable the player to bang the mom (for this type of games) it is technically (more or less) a "game over".
Ok, mostly there are some sisters, and|or other relatives and chars around to bang left, but the main goal of consumers (for this kind of titles) has been achieved. Yah, yah, theres still a story, open possibilities and..., but...
Story told. The Devs and Writers can add some variations in sexual techniques|fetishes and spin some story around the cold beef to keep it going somehow, but the main hook, or munition has been fired.
Every story has an end. Has to have and better a good, then a bad and boring one
