US$70 billion in spend aggregating data, back then, this number has only increased.
https://journals.sagepub.com/doi/pdf/10.1177/205395171454186...
So as a result, everyone keeps production in us-east-1. =)
us-east-1 is more a legacy of it being the first region so by virtue of being the default region for the longest time most customers built on it.
2) People who thought that just having stuff "in the cloud" meant that it was automatically spread across regions. Hint, it's not; you have to deploy it in different regions and architect/maintain around that.
3) Accounting.