If it wasn't for Ritsu, Mio would be in the Literature Club and the Light Music Club would have been dissolved.
If it wasn't for Ritsu, no one would have been in the music room to meet Tsumugi.
If it wasn't for Ritsu, Yui would have never seen the performance that convinced her that this was something she could be a part of.
If it wasn't for Ritsu, this show would have never happened.