But NoVA is basically the same sort of economic cluster that Paul Krugman won his Nobel Prize in Economics for studying, just for datacenters, not factories.
There's a great read about the whole area here: https://www.amazon.com/Internet-Alley-Technology-1945-2005-I...
As for AWS, I often see it repeated that the DCs are the oldest and therefor in disrepair. That's not true; many of the first ones have since been replaced. But there are services that are located here and only here.
But I'll also add, a lot of customers default to using US-East-1 without considering others, and too many deploy in only one AZ. Part of this is AWS's fault as their new services often launch in US-East-1 and West-2 first, so customers go to East-1 to get the new features first.
Speaking as one who was with AWS for 10 years as a TAM and Well-Architected contributor, I saw a lot of customers who didn't design with too much resiliency in mind, and so they get adversely affected when east-1 has an issue (either regional or AZ). The other regions have their fair bit of issues as well. It's not so much that east-1 necessarily fails more than the others, it's that it has so many AZs and so many workloads that people notice it more.
Why is that? You would think the company ending events like IAM going poof due to it being dependent on us-east-1 would be top priority to fix?
If you're building a single datacenter site this is where you start building first.
Coastal land much more expensive. If you go to a remote coastal site, you probably won't have as good access to power.
Coastal sites usually exposed to more severe weather events.
Other fun unpredicatble things eg-Diablo Canyon nuclear facility has had issues with debris and jellyfish migration blocking their saltwater cooling intake.
https://www.nbcnews.com/news/world/diablo-canyon-nuclear-pla...
In one of the slides, there were factors that influence the decision of where to build a data center, and several of the items involved finding a place with enough space and skilled people to work at this data center. He also commented sometimes there is politics involved on choosing the place for a next data center.
Toronto is the textbook example of this working. It's on a freshwater lake that is deep relatively close to the shore, and the downtown has expensive real estate blocking traditional methods.
https://en.wikipedia.org/wiki/Deep_Lake_Water_Cooling_System
Cold water -> data centre cooling loop - > warm water -> paper mill with heat pumps to transform low-grade heat into the required temperatures -> profit
https://datacenters.google/locations/hamina-finland/
> Using a cooling system with seawater from the Bay of Finland and a new offsite heat recovery facility, our Hamina data centre is at the forefront of progressing our sustainability and energy-efficiency efforts.