That sounds a very strange expectation. Most of my life post university I realized most of questions have complex answers, it is never as simple as you expect.
If the author would check how things biology and medicine work currently, I think he will have even more surprises than the fact that counting populations is an approximate endeavor.
>But it’s good to be reminded that we know a lot less about the world than we think. Much of our thinking about the world runs on a statistical edifice of extraordinary complexity, in which raw numbers—like population counts, but also many others—are only the most basic inputs. Thinking about the actual construction of these numbers is important, because it encourages us to have a healthy degree of epistemic humility about the world: we really know much less than we think.
Everything is basically a theory only judged on predictive capabilities. Even the idea that Earth is not at the center of the solar system is a judgement call of what we define as the solar system and center.
The math is simpler sure, but its arbitrary how we define our systems.