Didnt ayu passed them already? anyways, nobody is gonna replace who...they are all different. Nobody can be on top forever. Queen of Jpop doesnt really mean much to me. Its the music that matters. Ayu had so many great songs during her peak and now she have her awesome concerts as well. She sold alot of copies of those songs not only because she was popular at that time but they were quality songs with great lyrics too. She will be remembered for those...music and lyrics, etc. I just watched my dome tour dvd the other day and it is still awesome after so many years.

I was singing along to a song for xx, seasons, endless sorrow, etc. Lets just say I will never get embrassed showing ppl her concerts and music. (well maybe b&d)
I dont give a crap if her sales are dropping...yes they are dropping alot compared to her previous albums but they are still great for someone who has been in the industry for 8 years. Kumi and Ai can take the throne if they like, I dont mind. If kumi takes the throne, she should atleast produce better songs not like the ones she released this year. It will shut ppl up if she does. I really want to see how much she would sell without all those bonus stuff. It would be sad for her if ppl only remember her as her image, the 2 best albums, and the 12 single project and a couple of songs....(real emotions, cutie honey, butterfly, etc) Those are just my opinions btw. As for Ai, I like some of her songs and the fact that she write and compose her own songs makes me notice her more. I do feel she is quite limited though like her image and the range of styles in her songs. She also dont really fit the image of a queen....maybe coz of her cute image?
Anyways, to sum it up, nobody can replace anyone completely. ayu has done stuff kumi didnt and cant.. and kumi has done stuff ayu didnt and cant too. and nobody can stay on top forever. There will always be someone out of nowhere to take the so called spot of jpop queen. Cant they all be queens?