Is it safe to assume that's because they don't like using the service or because they are too busy to be spending all day on social media sharing posts and tweets?
The article points out that ex-executives of these companies say that the services were designed to capture people's attention and act like a drug, and that they now disagree with it. The implication of this (and to answer the title, I guess) is that current executives know this and "don't get high on their own supply".
Whether that's the actual case or not is the question, and we could compare other executives of technological but non social media companies to see the level of how much of their own dog food they eat. There's a further question which is whether eating ones own dog food is a good measure.
