The DNS is designed to provide resiliency to these kinds of problems by providing the ability to list multiple NS records located in different networks. It is standard practice for top-level domain operators and other high-activity domains to place their name servers in different networks to guard against these kinds of issues. When companies put all their name servers in the same network, they are removing the diversity benefit and create a single point of failure. Domain operators should take this as a cautionary tale that they shouldn't have all their eggs in one basket and make sure a single network failure couldn't take all their name servers offline.
There are many other single points of failure besides network failure, such as pushing the wrong configuration. In fact it seems to me that it would be rather rare for a multi-homed datacenter to have a network failure.
If you have a routing issue, whether it is due to "corruption" or misconfiguration, having some of your name servers on an entirely different network (i.e. a different AS) with a different routing policy is not going to be affected.