Most nonfiction books that catch the public interest have a certain amount of zip to them: The Feminine Mystique, Debt: The First 5000 Years; The Organization Man. These were books that not only bristled with anger, but also were full of tidbits and interesting anecdotes and, most importantly, stories. These books made sure to tell stories.
Capital In The Twenty-First Century isn't like that at all. It does not tell stories, except in the most broad and abstract way. It deals with generalities--the total amount of capital in a country; the total amount of income that the country produces; the share of income earned by the bottom fifty percent of the population, etc, etc--that are kept purposefully broad so that they can be compared across countries and across centuries. And it does some really fascinating things with those generalities. As far as I can tell, the book is saying that the move towards egalitarianism might've been a fragment of the twentieth century. And that the factors which caused it--external shocks that destroyed vast amounts of capital, combined with high economic growth that allowed growth in labor income to keep up with growth of capital--might not hold true in the twenty-first century.
But he doesn't go the extra distance and talk about what that might means: a return to a hereditary aristocracy. I'm not saying he's dry and colorless. He illustrates things just as much as he needs to in order to make sure that you understand (for instance, he loves bringing in examples from Austen and Balzac). But those illustrations are functional. He doesn't let himself spin flights of fancy.
All of which makes the book kind of tedious at times.
Still, it also means that you don't need to fall into it and become absorbed by it: you can just read the words. As such, the book requires less engagement than most books. Which makes it perfect to read during odd moments and bits of left-over time.