It’s fallen out of popularity over the years, but reading programming books. The big ones. There is an expectation that a book will contain every bit of info about a technology, and you can learn it, in depth, in one place. Online articles, videos, etc., often just skim the surface. You don’t get that deep learning and facts that the books would have. I find even “Official documentation” online is sparse and often doesn’t include examples to gain understanding.
Unfortunately, the pace of change, especially in cloud services, cause books to be out of date too quickly, so I don’t see it making a comeback.
I’d argue you’re right until you need to track down a bug in the code. Then, to the author’s point, you have to jump back and forth in the code to figure out all the interdependecies between the methods, and whether a method got overridden somewhere? What else calls this method that I might break by fixing the bug? (Keep in mind this example fits on one screen - which is not usually the case.)
The consultancy I used to work for in the late 90s would have crucified any developer that didn’t write “a data abstraction layer that allows you to pop off the original db and substitute a different one later”.
How many times in my 25 year career have I swapped out the database (and been thankful for such an abstraction layer)? 0 times.