Pregnancy content is EXTREMELY difficult to produce and manage, especially as a mid game mechanic. It still works as an ending and only Kali would be left out assuming Runey doesn't fit in a point where she goes off the pill in enough time before the ending. Then it is as simple as programming a counter that would set their ending to pregnancy if it's requirement has been reached or non-pregnancy if it hasn't. Glassix does the same and it works. You climax inside enough, she is pregnant in her ending. That also reduces the number of assets needed for pregnancy variants.
With an in game pregnancy system, he then has to make an entire complicated system in the code to handle the switch between normal and pregnant, which is nowhere near as easy as just a counter, and he has to produce assets for EVERY girl in ALL of their outfits so that they don't show up pregnant in one outfit and normal in the rest. He would also have to redo ALL of their events to show pregnancy if applicable because, once again, that would show the girl as pregnant outside events and normal in them, which doesn't look good. This is MUCH more tedious and time consuming to do, which is why most developers don't do an in game pregnancy system.
Also, there is magic in the game world, so he could easily come up with reasons why nobody is getting pregnant. Could be as easy as a spell cast on the hotel to prevent it. Then all he has to do is explain why nobody who has a sex scene outside the hotel is pregnant. Most depictions of elves show them as less fertile and not very easy to make a baby with. Couple that with literally everyone having some level of elven DNA and they all could have lesser fertility, leading to lack of pregnancy. Especially full elves like Lin, who would be under the full effect of her lesser fertility while other girls with more human DNA would get less of this effect, but still enough to make things difficult.
I get that you want pregnancy, but we need to be reasonable to Runey since he is working alone. It would be much more manageable with more than one person working, but that's not the case.