oh hey, I must be the other guy

Can you link a model supporting your statement? I wasn’t able to turn anything up showing a predicted population decline from 10 billion go 1 billion.

Project zomboid

Look into mask tape, it’s double-sided tape that goes along the inside bridge of the mask. I buy a pack of 100 strips on amazon and it lasts me a couple months. Cheap and easy and completely solves that issue.

Ana Diaz does a pretty good job of explaining it here

Unfortunately no, losing oxygen in a submarine is a bit different than losing it at altitude. The thing that makes you feel like you’re choking is the relative amount of CO2 in the air you breath. At altitude, the CO2 you exhale dissipates into the atmosphere and you drift off to sleep from hypoxia. In an airtight container the CO2 has nowhere to go, so you’ll die of CO2 poisoning way before you die of hypoxia. The worst headache you’ve ever had, your blood feels like battery acid, vomiting, confusion, then death. Not fun.

I mean it’s right there in the intro monologue: “to timidly stay where everyone has already been”

Only in the metaphysical sense. Be well, friend.