It's not your problem to worry about.

As someone else mentioned, most artists make sweet FA from CD sales. Therefore, buying new vs buying second hand doesn't affect many of them. This is the fault of the music business, and not you.

And someone also mentioned the resale value being a driver for new sales. I'm not sure as to the validity of this for most people. Certainly it might be comfortable to know that part of the $300/3000/30000 you spent on CDs could be recouped if an accident ever left you totally deaf, but the average person probably doesn't factor that into their shopping decisions. Some people may be of the type that buy everything, listen to it once, and then sell it - but I'd doubt very much that even 0.001% of people do that.

That being said, there obviously is a second hand market - so something in the music business's model must support it's existence or it'd collapse. What could that be?

Anyway, your right to buy/sell second hand CDs is protected. Thank God.