It's a bit like the statistic indicating that there is a noticeable decline in offending by psychopaths who survive into their fifties. You could say the decline in offending was due to their sudden rehabilitation...or you could be more in touch with reality and attribute the decline in offending to sheer age-related decline in physical health: It takes a lot of energy to be an angry, aggressive person.
Same with the elders: It's not so much that the current batch are more tolerant; just older, more tired and worn out...that's all.