The title says it all. This post by Domain Tools goes into more details on how Karl Auerbach, a former ICANN board member, told Name Intelligence (who operate Domain Tools) that the cost to VeriSign is far lower than they claim. This goes right along with my point that due to scaling, the cost per domain goes down, not up.

The other great point they raise is domain tasting - the ability to register a domain for five days and get a full refund. If the DNS was taking such a beating (as VeriSign claims), why even allow it? That would make a noticeable dent on all the registrations going on.

($6.00-$0.14)/$0.14 = 4200% markup = 97.6% profit (old).
($6.42-$0.14)/$0.14 = 4500% markup = 97.8% profit (new).

Poor VeriSign, they aren’t happy with their ‘little’ margins.

Updated: Steve correctly pointed out a flaw in my wording. Furthermore, for people with the typical “Don’t use them” defense - if you buy a .com or .net, you have to use them. Read my previous post.