McKinsey starts with the premise that the objective and mechanics underlying software development is known and well understood. In their line of reasoning, the only problem is that we're not measuring, and therefore that gathering more data and assembling it in a dashboard inherently will improve the process.

But as you allude, while it may be true that you "lose" 2 hours per day 3 days a week in some sense of productivity, that loss may simultaneously be the essence of some other sense of productivity. By suggesting it's "just data" and more of that is always good, McKinsey is (intentionally) glossing over / ignoring / hiding the fact that they will be doing the framing. (And that their framing is historically short sighted, superficial and often very wrong. See also: https://www.amazon.com/Big-Consulting-Businesses-Infantilize...)