Possibly, I think the writer is trying to cover himself either way in case the relationship doesn't last past college or if they do end up together but something sad like a breakup in the future or if one of them passes away (i.e. Erika's illness comes back and kills her).
Prequels help understand who the characters were. Don't get me wrong it will only matter if they don't explain how things that happens now began, if they don't explain then a prequel will be beneficial. How many VNs you've played that leave you wondering well how did this come about.
several actually. all start more or less in the middle of story, some give enuf info about what happened that no need for prequel.
As the story goes on I believe the MC will get answers. I think they will come slowly but, they will come. The question is how well the dev fills in the blanks... ? So far the past is shrouded in all guess work... also the original story was altered where the current "landlady" was intended to be the mom but because of patreon and idk if a report was made or if the dev just didn't want the worry/hassle but, it was altered so as of now no idea if we know who his mom is or if we will ever meet her...
