Looks more like an Open crack Pro rim ??
I guess the bottom line is the rim is worn out. None of them last forever and the fact that this rim might be designed more for lighteness(racing?), the MTBF will be much lower than a more robust "touring" or off-road type of rim.
Just wondering, what kind of brake pads are you using on those rims?? Could they be Modolo's "Sinterized" brake pads??, which I heard are rough on rim surfaces.
Chombi