Because the remix albums have stopped, and when remixes are produced they're only remixes of recent songs. Thus, no mixes of songs from 2003. For example...

— Moments single; featured remix of Moments.
— CAROLS single; featured remixes of CAROLS.
— MY STORY Classical; featured orchestrated versions of MY STORY songs.
— appears & UNITE! Drizzlies; featured remixes of appears & UNITE! (obviously).
— fairyland; featured remixes of fairyland & STEP you.
— HEAVEN; featured remixes of HEAVEN & alterna.
— Bold & Delicious; featured remixes of HEAVEN & Will.

>_<