Hmm even GREEN got Gold certification for Chaku Uta full and it wasn't even in top 100 ^^, it is still unknown how Sparkle and NEXT LEVEL did. Sure it does make sense the the old stuff prolly helped to some extent and even when it comes to Nishino Kana, Ayu obviously had more songs on Recochoku in 2009 than her.
When it comes to Chaku uta ringtones, now I doubt that THAT many people love having old and outdated songs as their ringtones especially with so many new releases and hip songs.
As for her popularity, we almost always say that Oricon doesn't show how much is someone truly popular (in most cases), but that the Digital sales are a better indicator of how much someone's songs are generally liked. Well there you go. While Ayu's image/figure might not be close to the popularity that Namie has right now, her songs are obviously way more popular than Namie's were this year (considering the Chaku uta/Full positions and not the overall ones) - and that's the fact
note that I am not trying to bring Namie down or anything, if it was Koda Kumi who sold more than 1 million of her previous album her name would be here instead of Namie's, but as the things are, Namie is among rare solo female artists that atm sell better than Ayu ^^