I don't think it's harsh. The author says that the rollout might be slowing. They justify this with smaller increase in coverage in the most recent update. But

I don't think it's harsh. The author says that the rollout might be slowing. They justify this with smaller increase in coverage in the most recent update. But the updates are not spaced equal amounts of time apart. So the actual expansion per unit time is continuing to increase. Compare to OS releases. Windows 10 gets updates every month, with feature updates every six months. Compared to before, these updates have fewer features. But they are coming much more frequently. Can we say updates are slowing, because they don't have as many features in each update? Or do we have to look at the features per unit time? I agree that it's not necessarily clear that they'll make their end of 2019 deadline.