It's not just Ayaka, for the most part the relationships in this don't feel "earned" really, they just are. By earned I mean you meet someone, you go through some stuff and your relationship develops (or maybe there's instant attraction but then take some time getting to know each other). Most of the relationships in this seem more like - you meet, you chat a little bit, you are deeply in love. Any relationship development that happens during time jumps doesn't really count as it isn't part of the story, and isn't even really talked about. The exceptions being people like Shani and Iraea, where the relationship basically existed before the start of the story and those relationship are discussed more than others. There also isn't much discussion of how/why everyone is cool with being a small part of a massive harem. Shani talks about it a little bit, but that's about it. As I said though, it doesn't bother me much. I still like the story, and most of the characters, it's just one of the shortcomings for me.