I believe they have stopped producing new copies. It obviously didn't do as well as they expected. I bought a copy myself, but I think if they made it even ten dollars cheaper more people would have purchased it.
Yeah. I mean, I only got it because I wanted a JRPG for the PS3, and Final Fantasy XIII isn't going to be out in the states for a couple years still. (Yes, I know there's Valkyria Chronicles -- but I couldn't decide if I liked it or not based on the demo alone. It's just so.. different. I'll have to rent it for a week to really figure out if it's worth buying, for me.)
Don't be scared of change, its a good thing. It being different is one of its strengths. You should definitely give it a chance. And demos usually harm games more than help them. You really can hardly tell anything from a demo.