Look at the reasons that people are dying. It's been blamed on things like the opioid crisis but the numbers in no way support such 'hypothesis', which don't even really qualify as such.

Cardiovascular disease, heart failure, stroke, diabetic complications, etc are where the big increases are coming from. And nearly all the major causes of death that are increasing are strongly linked with obesity, which is skyrocketing out of control. This is what I was alluding to early when suggesting that this change is, in turn, blamed on lethargic lifestyles, the internet, etc yet such changes are also happening in other nations yet they are not experiencing such radical shifts in lack of healthfulness.