Actually, going slightly off on a tangent here - in terms of actual proof that chains that are thinner wear out quicker than wider ones ie 10/11 speed v 8/9 speed, my awareness is down to stories I've heard about.
I am convinced that a wider chain is stronger however, as if there was no difference, then surely track and BMX bikes would have a thin chain. It would be lighter and more aero. They are wide for a reason, that they are stronger. KMC for example list their single speed chain as the strongest one they've ever made.
Another point is that I use Rohloff chains (8/9 speed). On my time trial bike, after about 15,000 miles, it had finally started to stretch so it got replaced. I tried the new chain on the old block and to my amazement it didn't skip on any of the sprockets. I realise of course that the SLT99 is regarded as the finest chain ever made. Yes I was sceptical at first - how could a chain be that superior? - but after using Sedis/Campagnolo Record/Dura-Ace etc it was obvious to me that the Rohloff is on a different level. It is a shame they don't make them anymore, but I do have two new chains so that should see me through the next 15 years!
Regarding snapping - yes agree that it could be due to incorrect fitting. 10 and 11 speed chains have to be fitted correctly; 9 speed and less seem to be simpler in this respect.