I love that people are trying to explain realism in a harem porn game set in the future.
So there are certain areas of realistically any game - whether it's adult themed or not - where you have to suspend disbelief, and realism doesn't really apply. However, having some realistic elements can help a game's immersion, can help one identify with characters, and such. Everyone has a different level of the ideal amount of 'realism' inside their fantasies, and some like having it in different areas than others. One of the reasons I like this game is because of how good a person the MC is. Regardless of whether or not the MC's harem is 'realistic' in general, it feels more justifiable to me because of this, than if they were a power and money hungry jerk that treats everyone around them as tools to be used. This increases my enjoyment of the game. It's a personal taste thing, but it has ties to what I perceive as 'realistic'.
I am under no illusions that this story could happen in real life. It is a fantasy. At the same time, if the MC, based on the story, and the world that's been created around the characters right now, suddenly developed magical powers, I'd not like that, because it would break the immersion I have, because it doesn't really fit with the world setting I've been building up in my mind based on what Braindrop has given us so far. This is where the idea of 'realism' is good to consider in any form of entertainment - it requires internal consistency. I think the discussions about US college athletes, and what is and is not allowed, fits very well within the relevance of internal consistency, personally.