i dont thiiiink it's meant to replicate them, i think they're just honestly crafted based on what sorts of fanbases would logically be based on each unit! and it just so happens that those types of logic tend to prove true irl as well.

i wouldn't be surprised if it's a tad inspired though, particularly with how ES expanding each unit's activities to be more general leading to characters having to deal with the fact they have new fans who may view them more casually or generally than how they used to; this is typically a !!-era writing narrative, which lines up a little with how !!-era expanded into a brand new market now that they became a rhythm game. and a lot of the in-universe fanbases are based off of general josei game fanbases (i remember even drama going down when Ephemeral Festival went down, since JP fans felt like they were bring written about just to be laughed at or disparaged by the characters)

but probably not too much past a light inspiring. it's interesting seeing the coincidences, like a lot of valkyrie fans note how the producers have a deep rift between their "new" and "old" fans, particularly formed via !-era and !!-era fans, but that lore about the in-universe valkyrie fanbase was in !-era!

probably going through the similarities might be a bit too much of heavy lifting for me to do esp since i'm not fully familiar with the jp fandoms