Why Avril can't make it in Canada or Japan

So as you all can imagine, Japan is all flooded with music. On a regular basis I'm asked if I know the words to a song, or an inquisition to my favourite bands... to which I follow-up, Spice Girls?
Japanese music- it's hard to walk around anywhere and not hear it blasting in the bars, clubs, and even classrooms. In all honesty, I have taken up the liking of many of my students' tastes in music- ranging from mainstream to pop- which is not much of a range of talent. However, I will admit that the music is QUITE catchy- not to mention the titles of these songs and bands. Bands such as GREeeeeeeeN, SMAP and Exile! are a hit, with the majority of praise going to female singers.
Ito Yuna, an American-Japanese singer has just released a new song called Koi was Groovy x2 http://jp.youtube.com/watch?v=uuZgdITZqXU
Koi" means "Love" and "wa" means "is"... so I suppose you can fill out the blanks. Without a doubt, my grade 9 students will most likely be singing the song by the end of the school term. At least they can say the sparse English words used in the song- I'm thrilled.
To go beyond the surface of enjoyment of music, the centralization of Japanese music has really been secluded from the outside world (the entire world), ironic, as Western music is just as popular as it was back home. Rihanna and Ne-yo are blasted through the radio stations, however, in asking about the knowledge of starts such as Madonna and Avril Lavigne they had no idea who I was talking about. This shocked me- however, it is a good representation of engrained the Japanese are in their own culture and neglect, however not intentionally censor the outside world. This is just one of the examples of how Western culture has not made it to this part of the world just as much as what we thought.
Maybe it can also explain why all Western artists put out Japanese versions of their tracks and records...not because it is a huge market, but because they need a different appeal than the West.