I have to respectfully disagree with a couple of points here. You say that if Pink Floyd were to come out it would be the biggest seller that HMX has ever had but keep in mind that there are thousands of people that dont even play this game anymore or have any idea of what music is coming out because they no longer care and dont check. Sad but true
Also I would like to point out that there really is no question of hurting or helping, the correct question would be am I helping enough. If you are purchasing anything on any weeks then you are helping keep this game and genre alive and kicking(which I for one thank you). I think they are still pursuing licensing for new music but keep in mind alot of what were getting was purchased a long time ago. So on that note you were going to get this music no matter what you bought.
Your current purchases may effect what new music labels and bands they go after. I would think if no one was buying any metal that they would stop pursuing licenses for new metal music. That is obviously just an example you cant kill the metal, the metal will live on. New-Wave tried to destroy the metal but the metal had its way!!!
Just my two cents