That depends on the failure. Plus what recovery methods, redundancy, and backups they have. However, even at current prices verasign should have no problem paying decent engineers. Especially considering the number of registrations.
However, the distributed nature dns does protect against a lot blunders unless they persist for long enough for caches to invalidate.
The largest concern would be bad backups of registration records. However, last I checked ICANN requires tld operators to keep backups and also submit those backups daily to ICANN. Plus other things so if the company/org goes belly up for some reason ICANN can manage it till they find someone else.
In some ways, it seems like the potential risks warrant Verisign to have a strong financial incentive given the problems we've seen at PG&E (if Verisign can also be considered a utility). Also, it does serve as a north star in regards to properly compensating companies or individuals who provide important protocols, infrastructure layers, and FOSS projects. How much that should be though is an interesting question.
However, the distributed nature dns does protect against a lot blunders unless they persist for long enough for caches to invalidate.
The largest concern would be bad backups of registration records. However, last I checked ICANN requires tld operators to keep backups and also submit those backups daily to ICANN. Plus other things so if the company/org goes belly up for some reason ICANN can manage it till they find someone else.