That's exactly why we might expect from the future science and high-tech to raise this percentage much higher. It's a fantasy, so why not? If they can make a totally different humanoid species to bear a human child, why they cannot perform a relatively simple gender transition?
As you pointed out, this is a fantasy. An alternate timeline, future sci-fi story, which could introduce a ton of possibilities, all of which are set by what the author decides is true.
While that does mean that there have been advancements in medical science, and that you have access to the tech and knowledge of more advanced species, societies, and cultures, there are a few other things to consider.
- The first, and easiest, is that it simply may not have happened yet. Might simply be that it will be a story element later.
- There could be something physiological that prevents that final step for Raene's species.
- For the first time in her life she feels accepted for who she is, so she may not feel the need to take additional action.
- At some later time there may even be a discussion with the MC where he tells her she's fine the way she is and doesn't need to change.
Regardless of what the reasoning is, there are two truths:
- Whether anything with Raene's physicality changes any further is entirely up to the dev.
- Each person reading the story needs to decide for themselves if their love for Raene is contingent on what's between her legs.
Once you figure that out, you can determine whether or not Raene is for you. It was clear from the moment that Raene's secret was revealed who she is, and there was an opportunity to continue or end things with her.
If you regret the choice you made, there are a few options. You can use a mod like URM to change your selection. Alternatively, it's as easy as starting over to change your mind. There are even ways to easily skip through the content back to where you are now with your new choices.
Personally, I look forward to seeing what comes next for all the characters. I'm enjoying the full harem, and eagerly anticipate what the author has for us in the future of this great visual novel; which I think is even better than their last.
Have a good one.