Maybe it has something to do with Takui/the fact that he has a version coming out too? Maybe the legal stuff just isn't set up between itunes/Takui yet, so we have to wait or possibly never get it at all (like with Mikaeri Bijin/Kono Machi).
That's a shame because I really like Taiki Bansei. It has a nice retro feel which I have a soft spot for. I kinda wished they has followed that though in the costumes though. I'm usually the one saying I wish they would wear more casual clothes in PV's and they have to do in in the song that was screaming out for sequins and platforms!
@Daisuki From the looks of it it doesn't look like Takui is going to release the song on his album any more. However I agree that it must be something to do with him why it isn't being released over here.
From a quote where he said that the song "was going" to be on his new album. But if his official site says it still is on it then clearly I was mistaken.
I just bought the Taiki Bansei and Otome no Gyakushu PV. Its really inconvenient to have to listen to the song via PV and also I really dislike the Taiki Bansei PV so its annoying to have been forced into purchasing it.
I suppose the other option is buying it from the Japanese itunes. I do have a Japanese itunes account... but I've always had to purchase a Japanese itunes card in order to put money into it and thats such a hassle.