Now for under $10,000, you can have a powerful computer, a DAW with almost unlimited tracks, a wide array of virtual instruments, and most of the other essentials for creating music in a home studio.
And without having a lot of musical skill or knowledge, it's pretty easy with these tools to fool people into thinking you know what you're doing.

Regarding how we composers have contributed to the devaluing of our own livelihoods, I like to refer to a video of a rant by Harlan Ellison (who I had a chance to work with many years ago). Here he talks about getting paid for your work:
http://www.youtube.com/watch?v=mj5IV23g-fE
Unfortunately, that train has pretty much left the station, but a little "I'm not gonna take this anymore" attitude, if massively adopted, might slowly get us back on track.
Richard