No major DNS provider would engage in a "Selective DNS Blackout" because of resource constraints - DNS is one of those protocols that is both embarrassingly parallel, as well as super efficient to serve. It's not unreasonable to see a well tuned, inexpensive (< $5K) DNS server provide on the order of 100,000 responses/second. And if you want to serve a million responses/second - just scale horizontally and add the resolvers to your VIP pool on your load balancer.

This article doesn't pass the common sense test. Not to say that GoDaddy isn't engaging in this selective DNS blackout policy, just that it's not because of a underinvestment in their infrastructure.