I get what you're saying, I share that philosophy but not completely. A realistic world would include an even share of straight women/men, a few LGBT characters, which should behave accordingly to their orientations, hitting/rejecting the MC accordingly on how you created him/her.
But remember where you are. Most straight players will want the classic one man-1000 women scenario where all other men are dead except them (I won't include the NTR, cuckold or swinger games here) or, if the MC is female, to have girls and men hit on her as if she's the dumb slut of the town with no diligence at all. No LGBT people at all, MAYBE the lesbians that magically like the MC's dick, or the rare femboy/sissy. Lesbian players want a world where people with dicks has vanished (let's put trans/futa out of this for now, it gets complicated with them) and gay players? a world filled with men, where women maybe exist but keep their pussies to themselves (ah, and they will chase the straight men on those games too. No men is safe there), and no futas/trans people there. Most people expect unrealistic scenarios here, you're the first one on F95 that I've read with such a vision for the game world.
This game tries to reach a wide audience, straight, bisexual, gay and lesbian. The easiest way to please that public WITHOUT angering the others, is adjusting everyone in the world, leading to those unrealistic scenarios. Most players WANT those unrealistic scenarios, they are here for the fantasy, not reality.