They kind of ran out of good diru to emmulate
In a way I'm okay with them being over. Their last two singles didn't have an impression on me like all of their 2015 releases did, and 〜reliving the old days〜 is such a broad topic that they could have explored, yet they kept a laser focus on only one flavor of it.
As much as I'd like to speculate that this was because of Ains pouring all of their money into Gossip now (like RR did with Avanchick), my dudes ran out of steam as soon as their 3rd album dropped (they had a song on it that sounded like they just didn't want to write the later 2/3rds of!!)
RIP homage-kei