Hmmmn, not sure I completely agree, SamT, as I've certainly had a few bolts pop on me over the years so it's absolutely possible. Top of my head: a Spit pulled out on Beardy down the Scialet de la Fromagere (a non-caver reading this thread would wonder what sort of kinky shit we get up to!!), a thru-bolt popped on Martin Groves in the Dachstein, and I've had more than a couple go on me but the only place that I remember was in Papua New Guinea & I think the issue there was that it was relatively soft & friable karst so we probably needed long thru-bolts with double sleeves. Saying that, I get your point about getting bogged down in the irrelevant micro-details, though...
The ease of bolting with battery drills has meant that somewhere along the line the caving world has down-skilled as a lot of the current batch of riggers have missed out on learning some of the fundamentals as poor skills get passed along the chain. We used to have a policy in Austria whereby nobody was allowed to touch a battery drill until they'd done at least two years of hand bolting & that produced some capable explorers. Sadly, that's not been a thing for quite a while which is a shame ;-/