> Mastering is pretty much EQing out the white noise.

huh?

Dude, it's a whooole lot more than that.
It's stuff like EQ & compression to make it bigger and fatter & richer sounding and making it louder. Making sure all your songs are the same level with properly timed space between songs. Editing beginnings and endings and adding fades & a hundred other things like storing and documenting backups.
In the case of a pro mastering house it starts from when the client walks in the door. The people who work with the artist, the facility, the equipment and the atmosphere. Most of all it's the mastering engineer and the experience he brings... not mention the multitudes of high end equipment he can access to make it happen.