Ok, I'm making one argument. In no real context. Make of it what you will and work out the rest of the arguments yourselves.
A lot of music IS really expensive. I already named symphonies as an example. In other cases, studio musicians are needed, that have trained for years and years, and only play in the studio, and need to get by playing that kind of thing. Or are you, on principle, against people making a living off of studio work? There is honest-to-goodness music out there that simply cannot be played without professionals. If anybody here likes jazz, he can hopefully recognize the amount of time needed to make one functional player. And that player is likely to HAVE to devote his or her life to it because that music is hard.
Studio production - good studio production - also takes time and CAN be expensive. Especially when many people are involved. Seriously, just because some people have been able to make music cheap in their bedrooms, don't start thinking that's all there is to music. And that that's ADEQUATE for music as a whole.
Like I said, I'm not making any other arguments. Just that making music is NOT CHEAP.