… politics determine who has the power, not who has the truth. - Paul Krugman

From the point of view of a modern economist, the most striking feature of the works of high is their adherence to a discursive, nonmathematical style. Economics has, of course, become vastly more mathematical over time. Nonetheless, development economics was archaic in style even for its own time. Of the four most famous high development works, Rosenstein-Rodan's was approximately contemporary with Samuelson's formulation of the Heckscher–Ohlin model, while Lewis, Myrdal, and Hirschman were all roughly contemporary with Solow's initial statement of growth theory.
This lack of formality was not because development economists were peculiarly mathematically incapable. Hirschman made a significant contribution to the formal theory of in the 1940s, while Fleming helped create the still influential of s. Moreover, the development field itself was at the same time generating mathematical planning models—first Harrod–Domar type growth models, then linear programming approaches that were actually quite technically advanced for their time.
So why didn't high development theory get expressed in formal models? Almost certainly for one basic reason: the difficulty of reconciling economies of scale with a competitive market structure.

Why did the magic economy go away? Hundreds of books have been written on that topic. This isn't one of them ― although I'll devote part of a chapter to some plausible stories and take a number of stabs at the issue along the way. But let me cut to the chase: the real answer is that we don't know. There are a lot of stories out there. Most of them, including the ones that have achieved the widest currency, are dead wrong on logical or factual grounds. There are some less popular stories that could be right ― but if you are honest with yourself, you will admit that nobody, yourself included, knows which if any of these stories actually is right.

There are three kinds of writing in economics: Greek-letter, up-and-down, and airport. Greek-letter writing formal, theoretical, mathematical is how professors communicate. Like any academic field, economics has its fair share of hacks and phonies, who use complicated language to hide the banality of their ideas; it also contains profound thinkers, who use the specialized language of the discipline as an efficient way to express deep insights. [...] Up-and-down economics is what one encounters on the business pages of newspapers, or for that matter on TV. It is preoccupied with the latest news and the latest numbers, hence its name. [...] Finally, airport economics is the language of economics bestsellers. These books are most prominently displayed at airport bookstores, where the delayed business traveler is likely to buy them. Most of these books predict disaster: a new great depression, the evisceration of our economy by Japanese multinationals, the collapse of our money. A minority have the opposite view, a boundless optimism: new technology or supply-side economics is about to lead us into an era of unprecedented economic progress. Whether pessimistic or optimistic, airport economics is usually fun, rarely well informed, and never serious.