Why do we like Bishoujo games? Is it not for the same reason we like video games in general? It allow us to do or experence on the computer/virtual world, something we most probably will not do in life. For example, I can’t remember meeting anyone who suddenly got a beautiful girl dropped right on top of them and wants to marry him. Or if one were to play darker games, burn, pillage, rape and be able to have 2 dicks and fuck 2 women with it at the same time. Or in more general terms, some of these protagonist seem to have the stamina of an Olympian cause they screw 6 women and cum 6 times in a row. Even in story based games, the number one driving force for stories seems to coincidence, which results in melodrama because of the said coincidence. Really, if real life that full of coincidence, I would have killed myself from the irony of it all long ago.
Most of these situations can’t be done or do not occur in real life, so we play a game that allow us to fantasies it. After all, we all want something we can not have/do.