Why not us-east-2 if you need east coast? Even so, I’m almost as far as I can be (in America) from us-west-1 and us-west-2. The difference in speed is barely perceptible when running services out west. In fact, I think my Lightsail PiHole is out there.
As I said, I’m not aware of any historical issues at the other DCs. 🤷🏻♂️
I believe us-east-1 is the default region so it’s probably a case of devs not changing their region unless they need to.
Also, 1000s of companies use AWS. In issue in any of their regions is likely to have significant impact on internet services
East 1 is the default, so you have something there. Not sure why a fault in any given region would affect others? My PiHole didn’t go down and I would surely notice a lack of DNS. :)