I am wondering whether this is subject matter specific. For math, I've heard Freeman Dyson write when he was a child "I had read some of the popular literature

I am wondering whether this is subject matter specific. For math, I've heard Freeman Dyson write when he was a child "I had read some of the popular literature about Einstein and relativity, and had found it very unsatisfying. Always when I thought I was getting close to the heart of the matter, the author would say, 'But if you really want to understand Einstein you have to understand differential equations,' or words to that effect." Later on, he goes on to say how he ordered Differential Equations by H. T. Piaggio with over seven hundred problems, most of which he solved over Christmas vacation. Then when he attempted Peter Eddington's Mathematical Theory of Relativity, it came very easily after the differential equations practice. Then for something like software engineering, I can imagine that a "project-first approach" as you call it may work well.