Indeed, for 20+ years of distributed data centers (remember AZs are generally separate DCs near a city but on different grids, regions are geographically disparate cities) we called it "shared nothing" architecture pattern.

Here's AWS's 2019 guide for financial services in AWS, where the isolated stack concept is referenced under parallel resiliency section and called "shared nothing":

https://d1.awsstatic.com/Financial%20Services/Resilient%20Ap...

But if they call it cellular architecture, it sounds much more exotic than a shared-nothing active/active service!

It's a common pattern in tech. Everything old will be new again.

To me it seems without the art. The costs will be passed on to the customers. I think there must be good ways to do redundancy without having all services running at full blast in each Availability Zone.

It's a blunt tool, much like PHP. PHP does seem to be a good choice for them, but I wouldn't want to work there. It's all right, there are different ways to do stuff.

Oh hey they now have a new buzzword to sell!