This is more a general response that was sparked by your comment and some others over a direct response to your comment, if that makes sense.
The problem is that there really isn't one, which is why having a harem option is almost all ways the best course. Harem fans tend to understand the point of things, it's all a fantasy anyway so why not just let the fantasy play out its natural course. They are willing to accept that the whole thing is built on the improbable. The Mc is a special case, he is the main character of the story and nearly everything else fits with that, good and bad. He has tragedy that very few others will have, he has highs that most will never have. He's "lost his parents in some tragic accident," he is the "best basketballer," or the "smartest guy in school so he got this or that scholarship," and other such already fantastical events. No one guy is going to be courting more than probably one chick at any one time let alone a half dozen or more anyway. Many girls in the modern era will not be okay with you not committing as soon as possible and still fucking around, and the ones that would be okay with sharing the MC while he gets to know everyone else aren't likely to suddenly change their mind just because suddenly it is "the end of the game." There are some women who will share, as evident by history, even some who might not think they would, will, under the right circumstances. Embrace the fantasy, you know?
So, non-harem AVNs have a conundrum that is nearly impossible to solve. It is funny, harems are so easy to make that many games make them by accident and then at the end realize, "wait, how did this happen," and rush an ending where suddenly everyone changes personalities and suddenly starts giving the Mc ultimatums which come out of nowhere. If I was dating five chicks and one suddenly came up to me and said, "Be exclusive to me now," I'd respond with, "Um, no, where did this come from?" That or the Mc is a cheater hiding it all, which means he's an ass and if the girls found out he was cheating and hiding it from them all, then likely none of them would stick with him, let alone care who "he picks." Imagine it, the Mc saying "I know you just found I cheated on you and banged all these other girls all this time, but I'm picking you..." If she thinks she is exclusive and finds out she isn't, it is not going to be a good time for the Mc,
If a game has, say, six possible girls, by the time you meet girl six (often in the third update and months/years into the game for most games at the earliest because of how the dev cycles here work) the other girls have sex scenes, developed personalities, and player buy in. The later girls will always be harder to introduce in a way that doesn't make things awkward. Like you now need to break the other girl's hearts for this girl you don't know. If you introduce six girls at the start and then say, "Pick one," well, I don't know any of them, how can I pick? But if you spread it out, then the early girls have such an advantage and at that point picking a later girl changes the whole dynamic of what was happening with the earlier girls. And if I do take the chance and reject the first five girls in the hopes that girl six is good and she isn't... well, that was a waste.
Either:
The game is a harem with optional chances to ditch girls you don't like.
The game works like it is a harem until all the girls are introduced in a natural flow for the story, and then the girls who were okay without commitment suddenly aren't... at which point just make it a harem all the way, why suddenly change things?
The game introduces all the girl right away and forces the player to pick before they know any of them and just hope you got a good one. Which often makes the story feel rushed and awkward because it all happens so fast without any pacing and build up.
Or the game forces you to pick the first girl as soon as you meet her and miss out on other girls and just hope that if you reject the first girl one of the other girls is worth it. Meaning you are locked into, or out of, the end games before you even get past the first conversation with the first girl and any other content is just in the way and makes you miss out on everything.
Seems to me it is clear which is the best option,
I hope you all enjoyed another JoeTheMc essay,