I agree its "common knowledge" but is it true? Or is it just a case that because 80+% (made up) of everyone hosts in us-east-1, thats the only one we hear about in HN (and other sites) threads?
I go by the outage reports published by AWS. I haven't done an exhaustive analysis but there is a trend to support the common knowledge. I spend most of my time in us-west-1 and us-west-2 and very few if any outages over the past 3 years.