Been wrenching bikes since the late-60's, and I've built and repaired a lot of wheels. Now that I think back, I don't recall seeing a front wheel with a snapped spoke. Oh, I've seen taco'ed front wheels, and curb-crashed rims, and so on, but never a spoke failure akin to the ones you see on the drive-side of a rear wheel. Thinking even further along these lines, the only broken spokes - from normal riding - that I have ever seen were on the rear wheels of derailleur-shifted bikes. My first job was in a Raleigh shop, and I have worked on many Sturmey-Archer IGH, and I do not recall ever seeing a broken spoke, only from freewheel/freehub wheels. I suspect it has much to do with the dish needed to clear the gear clusters.