[Crystal_Ageha]

Sunshine, I think Ayumi didn't know what to do with her music career when she did the rap record. And I'll also give Namie the benefit of the doubt and say she didn't really know what she wanted to do when she had more dance influenced music at the start of her career.
But now she's changed from her "real" style back to a similar style, which just happens to be popular. And she changed to hip-hop (or hip-POP--WHATEVER--that's, in my opinion, just her way of trying to make everything better, because everybody knows that she was trying to be real Western hip-HOP) when it looked like hip-hop may get big, after Hikaru's burst. It's not a matter of variety, it's the fact that she decided to completely "reinvent" herself at the exact time after a certain style started to get attention. Yeah, that's technically variety, but it's also technically selling out. The way she experimented between songs on PAST<FUTURE itself is how you are supposed to do it (that's considering if, of course, that's really what you want to do, and not just a selling point).
You guys are bringing up other artists... Kumi has ALWAYS had this: a heavy beat mixed with pop, often making it into a hip-hop or techno influenced song. She's experimented, but that's always been the core. So, not a sellout. I DO believe Hikaru sold out with her last English album. But not because she went from electropop back to R&B, but because that album obviously wasn't who she really is. Just like how all these changing of styles isn't what Namie is. At least, that's not what she tells us. So if she's a person who loves to experiment with every album, incorporating each time major elements of what's mainstream...then that's fine. But she's said for years now that she was something completely different, so THAT'S why she's a sellout, not because she has variety, or even if she goes in a different direction (like Utada did, starting with Deep River). Well, I take it back... I guess she can either be a sellout or a flat out fake. Your pick. But it's definitely one of those.