Kinda makes me wonder if hololive just has less drama or if they're more professional mitigating the drama.
Hololive used to have actual drama. Like management being forced to apologize for incompetency due to the permissions issues, or failing to provide support to Mel when she had a stalker until she lawyered up (if Vox comes out with a statement like Mel did people will
crucify Anycolor). Difference is that Hololive seems to have improved a lot. I think Nijisanji has improved when it comes to handling JP talents but is very inconsistent otherwise. The goodwill Hololive has means that minor incidents can be swept under the rug. If one of the NijiEN talents gets caught selling traced artwork for example it'd be quite a huge deal even if they apologized to the artist. A Hololive talent more or less got away with without being flamed.
In regards to exID, it seems like AnyColor merged them and axed all their management without properly replacing them, so they fell to the wayside.
Ironically, I have heard exKR is actually doing better since the merge, but that may be heresay.
I think KR ironically benefitted in a way from not really having as much of a strong branch identity or sense of unity prior to the merge, meaning that the people who weren't interested in continuing on left. Given how many of them graduated prior to the merge it is relatively safe to say that the ones who stuck around are ones who were fine with just being thrown into the general pool of JP livers. They went from bad management + a probably toxic environment (with Ara and whatnot) to what at most seems to just be fairly hands-off management and not much toxicity.
In terms of how they're doing, they're mostly still chilling in the bottom half of the chart in terms of subscriber account (with Ryu Hari being last) but a fair amount of them (Seffyna, Nari, Nagi, Ha Yun, etc) have carved out pretty loyal followings and seem happy enough. I can't know what they are thinking but we haven't seen the sort of passive aggressiveness that we've seen from the ID livers.
ID meanwhile stuck together, probably in part because they had a much more cohesive identity and sense of camaraderie. The result though is that they might have stuck it out for sentimental reasons instead of realizing what what clear for just about anyone to see - the merger meant no more Nijisanji ID, plain and simple. If Anycolor wasn't going to change anything, they wouldn't have done the merger. ID went from pretty hands-on (though arguably a bit overly controlling) management that made them feel, well, taken care of, to hands-off management.
If you were looking only at numbers you probably couldn't say that ID is doing worse than KR since the merger. ID numbers haven't really fallen off or anything. They were pretty low before the merger, and pretty low now. Even with the support they were getting they were trailing far behind the likes of HoloID and Maha5. But the other things besides numbers seem to have contributed to a positive environment prior to the merger, and those are gone now.
Basically, KR's low point was well before the merger. The ones who are still around are ones who remained through that period. ID, on the other hand... well I wouldn't be surprised if it's their turn to have a ton of graduations.
These two are the ones off the top of my head that blew up and would have given Niji reach outside of their regular Vtuber watching fanbase but they did nothing with it.
Difference is that the JK-gumi girls don't speak English and thus probably wouldn't have converted a slight meme bump into anything long-term, especially given that this was back in 2018. It's like if Miko's "nigga" moment was just a one-off - it would have led to memes, a brief bit of interest, and that's about it. The difference here is not with the decisions of the talents but the timing and response by the company. Single members rarely ever lift entire branches or agencies on their own, and single memes definitely don't (otherwise "winning son" meme would have made Holostars massive).
