In theory, Weasel the butted spokes may save your heads because of the elasticity arguments. But there are probably 5 main reasons heads fail, of which butted is only one reason. There are also a bunch of specific building things that can address head breakage. I think the main thing is that people decide they don't want broken spokes on tour and then they latch onto the idea that experts say butted spokes are better, and they jump to conclusions. You did nail the main reasons some people prefer straight spokes. I recently laced up two new wheelsets, and was surprised at how little price difference there was between the two types.

Another issue is whether touring is really a long distance use. A long tour for most of us is probably less than 5000 miles, so if spokes are breaking within that kind of distance it isn't the spoke butted vs. straight.