And how you would know to do that, if you're not writing code?

It's my impression that the best way to be able to read code and distinguish good from bad is to write code. Get burned a few times and you know why certain patterns are a bad idea. You don't internalize that equally well from a powerpoint slide.

Compare this to math. Every successful mathematician has gone through the motions of proving certain basic theorems in math. Like Euclid's proof that there are infinitely many prime numbers. And then they went through related exercises. This was all learned with sweat. The statement above is akin to saying there is no point in doing any proofs by hand anymore, just read one and you will have sufficient understanding of mathematics and become a good mathematician. I don't think that's true. (And I also believe that many sw eng people would be better at their job had they groked the proof of the halting problem.)