1) I think all of those songs were released on RBN after they stopped doing the Wii. "Blue" is RBN2, which is definitely out of availability.
2) The music you're complaining about that didn't sell well on the Wii sold well on the PS3, and HMX has ported over almost all of the top RBN songs to the PS3 at this point as a result.
3) DLC doesn't sell as well on the Wii. Period. Even HMX DLC is significantly outsold by the PS3 over the wii (by a factor of 5-10 if I recall correctly).
4) RBN conversions to the Wii required a lot of work. They effectively had to rebuilt the file from scratch. Sure, the charting was done, but the format change required a large amount of additional time. Combine this with point 3, and the cost to income ratio is significantly lowered. Meanwhile, on the PS3, it was a fairly simple header change and a few tests.
Just to look at a few numbers, here are the top 5 selling Wii RBN songs in leaderboard plays.
I'll let you crunch the numbers, but end result: Wii sales were not very good. (I had a longer post here, the forum ate it).
Song Band 360 PS3 Wii Total
Higher Creed 25,394 11,570 2,994 39,958
Paralyzer Finger Eleven 21,135 9,300 2,541 32,976
Bodies Drowning Pool 32,188 14,160 2,247 48,595
Semi-Charmed.. Third Eye Blind 14,789 7,222 1,629 23,640
Nom Nom Nom.. Parry Gripp 8,605 2,811 1,384 12,800
Fake It Seether 16,545 6,786 1,364 24,695