I think it's crazy how $100k seriously can't cut it in the US?

Here where I live, in Norway, $100k is more than enough to live very comfortably almost anywhere in the country. Only exceptions would be certain expensive parts of Oslo, and some other high-income areas/towns around Oslo.

And if you're two people earning that kind of money? Early retirement would be a viable option in as little as 10-15 years, if you have a sober lifestyle.

But, then again, I have friends and ex-colleagues that live in the US - and I'm not talking about expensive places like NYC, SF, etc. - bur rather medium sized cities in flyover country, and even there people are paying rents (or purchasing homes) that feel pretty stiff to me.