Quoted By:
I completely agree.
Hololive EN is a lot more popular not only because they have a wide variety of content that appeals to a wide variety of people, but their talents are also very normalfag friendly. People love a cute anime shark girl who acts silly on stream and throws in a few memes and sexual innuendos every once in a while, or a gaming gremlin who likes to tease their chat.
On the other hand, Nijisanji are all former indie VTubers who appeal mainly to otakus and vtuber fans. With the exception of maybe Selen, the things these girls talk about on their streams is a bit more niche that casual anime fans who only got into vtubers in 2020 may not care about.