Why does Rock Band get the most attention from artists?

[venepe]

soulsamurai said:
Rockband gets much more digital downloads then guitar hero, put it on the software where people buy more.

But that is a catch 22 kind of argument.  It gets more download because it gets more artists.  GH gets like 3 songs per week, and RB gets up to 10.

And GH started the DLC before RB (with GH2 in the Xbox360).