Well Kumi's last time with a studio album was 2007 (Oricon Year) so I think she could do it again if some miracle happened. The last time Ayu had an album sell over 1m according to Oricon was in 2004 and the last time for Namie was 1997.
Namie's last million selling studio album was in 1997 because that was her peak.
Each diva got million selling albums during thier peak. Namie scored a million selling album during her 2nd peak in 2008 although that was a best album.
Let's not try to lesser the achievements of the 4th highest selling Japanese female artist of all time
& I can't find a link to Enrique's Belfast concert 
and PROUD! 
on the UWC?! 
