Verisign did not take a risk by developing the dns system - network solutions did that. Verisign maintains a perfect monopoly over the addition of records to a central database, with minimal operational costs. Their business is almost pure profit by operating a mandatory service with highly inflexible demand. If they were forced to compete on providing access to a core internet infrastructure (e.g. allow competitors to also add records to the .com registry) the price would lower to the actual cost of providing the service, which for an update/add query, I suspect would be in the pennies.

Network solutions did not develop the DNS either.

What risk did Verisign take, and how would the Internet change if they weren't rewarded for it?