I saw that this morning! It made me really happy. The wide range of idols made me happy, too; Matsuda Seiko and Matsutoya Yumi are still so loved. Ayu can be, too. <3
I'm not surprised at the lack of Koda Kumi or BoA, unfortunately. BoA's name is mud since the drug scandal, which is hideously unfair, but Japan is very strict about that sort of thing.
And Koda Kumi just hasn't been in sight for a long time, though she's still making wonderful stuff for her fans.
As for Reol, she had a big year for her, but I never saw much about her in the news or on TV. Same with milet, which surprises me, because she had a number one album (then again, these days those sales don't mean much--idols keep getting the top spot, while almost no one but hardcore fans know anything about them). Whenever they do have articles online, there are never any comments--(to compare when there's an article about Ayu, there's dozen of comments at least, if not hundreds). The public overall doesn't know them and they're still pretty niche (which, again, surprises me with milet--maybe one particular subset really likes her, like women of a certain age?) Particularly if you're talking anyone over thirty or so, they wouldn't be known.