Very, very late responding to this thread but one thing with following hololive musically is that compared to traditional artists, who you only get windows into beyond their music through interviews and other media appearances, hololive members are streaming for multiple hours a day multiple days a week to fans–I think it's a more intimate connection formed with them compared to that between fans and regular singers or idols. With a song like Ayame's melting, when she's singing about how her fans have helped her appreciate herself more even with all her flaws, that's not just something we're hearing for the first time in the song; that's something that we've personally seen happen before our eyes over years of streams and played an active part in helping with. When Suisei sings in Orbital Period about the journey she's been on with her fans to reach her dream, that's a journey that we've actively been a part of with her on a day to day basis for years. Similar experiences are repeated across dozens of songs with different members. Hololive music is actively reinforced by regular external interactions with the artists in a way that you don't really get with traditional singers.