This is what I'm thinking. If Tsutsui wants each ending to be convincingly considered as canon, he'll probably have to give the same amount of content that he gave to Uruka here. Since Chapter 150 ends a volume, and this arc has been 9 chapters long, we can reasonably expect that the other four girls' endings will be the same amount of chapters. Perhaps to really hammer it home, the ending volumes could all be the same number, just featuring different girls. Or it could just brand itself as We Never Learn If or something.
Essentially, with this decision, WNL might've bought a ticket to 2021...though, I don't see it going past January. This idea is quite novel, and I'm hoping that the other sides of the story are relatively well executed. There's pros and cons, but I think this is what WNL will be known for at the end of the day. Maybe other stories like this can implement this type of ending for popular characters that were never going to win.
Also apparently the Bokuben sub is praising Tsutsui now for what he's doing and I find that absolutely fucking hilarious. People were really only salty that they didn't get their Sensei end, and I'm seeing people taking the decision as him wanting the Sensei end the most. xD I'll wait for that, since I'm honestly curious about how that'll play out, and also the Fumino end arc as well.