" I'd like to see a competent argument that shows this is not complete bull manure."
We're coming out of not one, but two historic events. First, opioids took out a lot of folks, at a relatively young age. That made the overall longevity averages drop. The next historical blip was Covid: older folks, in general, but many more, particularly those closer to passing anyway, due to age or poor health.
Take those folks out, and voila! All of a sudden, longevity predictions spike.
It's macro math, nothing more.
" Young aren't drinkin as much..."
DUIs have dropped in states with legalized recreational marijuana. Go figure.