Yamada Kanehito (the author) really came full circle with frieren: (chapter 1) https://mangadex.org/chapter/894186/10 , reading both at the same time is a double whammy.
Yeah, NYC does so well in handling the Kung Flu, that surely there would be survivors if a genuine extinction-level threat were to hit all of the population centers.
@MisterXiado Imagine if every person on NY died early. It would make sense for survivors to get there to get the resources like all the food and water stored that was never used because people died anyway. lots of canned food and bottled water for a large city and only a fraction was used.