Our own applications are hosted on Azure, but we had an outage today anyway. It was because apparently Netlify and Auth0 use AWS and went down, which took down our static sites and our authentication.

The nature of our business means it wasn't a big deal, but I could imagine lots of people were in the same boat.

But the colos aren't usually managed by a single control plane controlled by a single company, so while they can all fail, they will generally do so independently.

Certain "global" AWS services depend on a specific region (us-east-1 if I recall right) so if that goes down you could be in trouble.