Probably because we're 4 episodes in to a game with an expected minumum of 12 episodes and a maximum of 20 and these are 2 of the 5 main girls. Cutting off main LIs, whether it's them, or Sage, or Bella, so early on in the story isn't something that's generally done in most games, so it's hard to wrap your head around the thinking process here. I mean, what's the point of them still being on the end of episode summary if they're no longer LIs? I highly doubt that they'll be replaced with other characters because that means more branches, more variables, and more time needed to be spent on the renders and animations for each update.
There are plenty of ways they could become viable solo LIs later on and I've seen plenty of people say they'd be open to that, especially some of the Josy fans who don't have much interest in Maya. To basically just be like, "nah, it's threesome or nothing, take it or leave it", seems like a really odd thing to do this early on when there's still so much potential for these characters.