I think there are 2 reasons why Utada will never make it in America no matter how great her music is:

1.Japanese people in America make up such a small segment of the population that she doesn't garner enough support from them to propel her into the mainstream like a other minority groups(blacks and latinos)

2. Top 10 POP Radio Stations are rigged ( CBTM was # 1 on many smaller stations around the US but didn't even get a spin from the Big 10) The Top 10 Pop radio station in my city flat out told me that they would not play Come Back To Me no matter how many people or how many times I requested it and he gave me no explanation why.
Can anybody explain this to me?

When I was younger when you requested a song on the radio the DJ would play it especially if many people were requesting the same song. Now i think the record label has to pay a bunch of money to these stations to play an artists music and since Utada is an unknown and doesn't have blonde hair,blue eyes or is from American idol or the Disney channel the record label will not risk losing money in investing in a "foreign" artist who keeps her clothes on.

Utada eluded to this when she spoke In Hawaii back last year. I think you can find the interview on Youtube or on Da Bomb's ( Honolulu radio station) website.

These Big 10 pop radio stations pretty much dictate what is a hit and who becomes popular in the US nowadays.

Do a google or wiki search on PAYOLA.