. It's hard to troubleshoot the problem in the abstract.
agreed, I worked at my bike shop on the north west coast for six years, didn't see anywhere as many bikes as most city shops but my recollection is that most spokes broke on the drive side. For all the spokes to break on one side of the non drive side flange leads me to think those spokes were weakened compared to the drive side from day the wheel was assembled. It's just too consistant.