But data centers are typically designed with network and power failures in mind, not? Isn’t this why these kind of ring based network topologies exist, so that whenever a single network connection fails, it can still easily be routed around?
Almost always, yes, but the problem is that everyone has to start routing around the problem and it creates congestion. Those redundant pipes don't sit idle. They are sharing the traffic.
As mentioned in another thread, in this case, Google has rerouted google.com traffic out of the region to try to mitigate the congestion.
On a smaller scale, to link up a few datacenters that are a few miles apart? Sure. On a grand scale though, no. Nobody's running an extra undersea cable from Japan to Singapore so that they can have a ring topology. Or trenching a second PBps of cables across the Appalachian Mountains. When something like that gets busted you go and reroute your least important traffic and send out the repair crew.