It's not the spoke lacing!
There are millions of half-radial wheels out there that aren't wearing funny.
My hunch is that one side of your rear brake is making contact first, maybe it even rubs sometimes when not braking, and that's what is wearing it faster. Next time you adjust your brakes (you do that, right?) take note of whether both pads hit at the same time, or whether one side moves more freely than the other. Sometimes you have to settle for unequal brake pad clearance in order to adjust both to hit at the same time.