When you remember that Lynn is extremely reluctant to admit the possibility that she could be what social scientists call an outlier and what laymen call 'that creepy little girl who got love-sick too early,' she doesn't want to admit that boys and girls got themselves into packs and didn't like the idea of consorting with The Enemy much. While her peers first started to warm to the idea of being friends with girls when they were in their early- to mid-teens, Lynn couldn't admit that her third-grade chums actually meant it when they talked about how icky boys/yucky girls had cooties and the like because of the primal dread she has of not being normal. She thus seems to have come up with her usual protective mechanism of assuming that everyone is really just like her so she doesn't have to be alone and swarmed by people who want to tear her down.
Thus do we have to trudge through slop about how Deanna and Mike were destined to be together and why it took so long for Lizzie and Chris Nichol's replacement to finally have their almost last chance when reality would have them drift away. It's not just Lynn's reluctance to create new characters that's in play. We also have to deal with her inability to admit that elementary school isn't Peyton Place with juice boxes.