I'm just over 10,000 miles on the original Thorn chainring, I expect it to do another 10,000 miles when I turn it round. With a perfect chainline that's what I'd expect, what are you doing to yours? If you want to try steel, Highpath Engineering will sort you out.
EDIT - Ah yes I remember what you're doing with yours, running it covered in mud[:0]
My front mudflap almost touches the ground, so the drive stays pretty clean. It makes a massive difference on any bike.