Anything with enough friction on it is going to smooth out eventually. One thing I suggest is to thoroughly clean and scrub your g10...it may be all in my head, but it feels like it brings the texture back out again. Maybe there's something that sticks to G10 gradually. It certainly won't hurt your g10, at least--it'll come out looking much better.
I haven't had a g10 folder but maybe six months, but it has performed well. I cleaned up four or five months in and it looked like new again.