As a professional environment artist myself (and having just released a book about it) I can attest that yes, environment artists can make a good living. In my experience in the game industry, there are usually more environment artists than any other kind of artist, simply because the asset list needed for your typical game is much longer for environment assets than, say, characters and effects.
For the game I'm working on now, for instance, we have a team of 6 environment artists and 2 character artists.
As for what exactly I make, feel free to take a look at http://srv01.simply3dworld.com/showt...threadid=33151
where I posted a portion of the work I did for my last game project.