Akane really loves purple (violet), so, tbh, it kinda surprised me that she didn't got the color. It makes sense if they didn't had the final say.
Edit: Sorta related, at first I was somewhat mad when Maachan said that she didn't wanted to give Tanaka's light blue to anyone because imo she didn't the right to say that and it would be unfair for 12th gen. However, I now get this feeling that all of 9-11 gen had a mutual agreement to temporarily retire the colors. They were all very close with Tanaka and (mainly) Michishige, so they must have not wanted their member color, which symbolizes them, to be replaced so quickly. If that's the case, then I'm not even mad about them being retired for now.