Can one person has more benefit going solo than within a group? It's said Rika Ishikawa has more fans than Morning Musume as a whole, although many of them are not interested in Momusu nor Viyuden. Is that possible?
That ain't bullshit. For example Miki as a solo artist will always sell more than Country Musume + Miki. However I don't believe that any of the MM girls would outsell Morning Musume. If Maki and Nacchi couldn't do it, then Takahashi, Reina, Yossi etc. won't do it either.
And about that solo vs. group thing. I saw a funny comment about Viyuden in 2ch a while ago. People were talking about the weak sales of Viyuden and someone said something like that total sales of Viyuden (10 000 copies) consists of Rika (15 000) and Yui & Erika (-5000).
Even though it was a joke there is still some truth in it. The name Rika Ishikawa is still more well known than Viyuden. I saw a japanese google hits chart and the name "Rika Ishikawa" had twice as many hits than "Viyuden", "Erika Miyoshi" and "Yui Okada" combined. So I definitely believe that Rika herself would outsell Viyuden. Another example of this is that when people were talking about the sales of Fleur de Fleur some Rika-fan said that why would he buy a Viyuden PB if he didn't buy Morning Musume group PBs either.
And I understand that. I'm a Rika-fan and I only own three Morning Musume releases: The Peace single, Osaka Koi No Uta single & Rika graduation concert DVD. If Rika would have gotten solo singles while she was in MM I would have bought them. I never had any desire to buy singles like Namida or Manpower because they don't have as much Rika as The Peace.
I think the difference is even bigger with a big group like MM. I'm sure all Tsuji-fans support W and most of the Rika-fans probably support Viyuden but it's pretty hard to support a group if your favorite member is just one of 10-15 members. And especially if your favorite member doesn't get many lines or much screentime.
I believe that the first solo single by any popular member could sell around 15-20k but the next singles wouldn't do as well. For some reason hardcore fans tend to buy multiple copies of debut singles/PBs. I think Miki and Takahashi could sell as many copies as Nacchi's, Aya's or Viyuden's latest releases.
That was a lot of off topic crap but anyways, the only members I could see going solo are Miki and Takahashi.
Takahashi - going solo? She'd probably do about as well as Kaori is.
Takahashi would definitely sell more than Kaori. Takahashi and Miki are the only MM members who are considered as popular as the DEF. DIVA girls.