I think you forget that SMAP's final best album release SMAP 25 Years sold more than 1 million copies in less than a month
It's still charting/selling on Oricon as of now & it was released last Dec
http://tieba.baidu.com/p/5331013080?pn=2
Same with Finally , SMAP 25 years was reasonably priced - 4,212 Yen for 3 CDs regular & limited versions