Although I agree with the science behind the Last City being located in Chile, I always felt the cultural element doesn't support that. We see clear preservation of various cultures within the Last City except Chile and native cultures, Festival of the Lost aside (and even then, that's a stretch). Mulling it over, it seems native villages would have a high survivability rate due to lack of interplanetary tech sought by the Eliksni, unity of the community, regular use of localized resources for survival, and possession of firearms and other weapons/strategies for self defense. That being said, there is either a plot hole in D2, there was another genocide within D2 during golden age that isn't mentioned, or Chile isn't the location of the Last City Many may not care about this but it would definitely add to the scope of the D2 world and lore.
Guess what.....I don't care where the Last City is.....why? When the First Collapse happened.....Cities, Towns, Countries, Nations, Kingdoms all Fell. Which is why the Last City is called the LAST City. And not Washington or Beijing, or New York City.....it's the World beginning anew. Everyone United under 1 Being. Not as separate people...but as one. Also, Old Items..... begin to Degrade over time. It's been bat least 5-7 hundred years since the Collapse. Only thing we will find....is fossils. Unless its golden age Tech.