I find it interesting that the lowest paid person is the CTO. (Director of Sales will make more because of bonuses).
But I'm going to assume this article references companies where the Technology department is more of a cost center than primary operations.
For example a SaaS company that basically just has sales/marketing and technology/operations, the CTO is also acting as the COO, so I think you could attribute the COO salary to that of the CTO in a SaaS or high-tech startup.
(Then they broke and go insane from the perceived injustice, see that other article recently...)