Are homogenic nameserver names a single point of failure?

The golden rule of security, stability, and resiliency of virtually anything is “don’t put all your eggs into one basket”. This generally applies to the DNS, and there are some recommendations to avoid having all your nameservers in one domain. I would like to show that in this case, this is not a silver bullet, it depends on many conditions, and using different domains in your nameserver set might even make things not better, but worse.