I'm a marketer who has become more and more technical over my career. The amount of opportunities that has unlocked have really been worth it for sure, but it also simply lets me be better at my trade than those who do not have those skills because I see connections they may not, and I can implement those things independently or with fewer resources than others.
It also frankly just makes things more interesting, because when I think I've reached the bottom of a rabbit hole and risk getting bored, suddenly there's this new tunnel branching off of it that I can explore, and before I know it, I'm delving into expert-level problems of a part of my industry I've never considered before.
I think these are the people the author is referencing. These students did amazing if measuring by GPA, but did so through hard work and a lot of thinking. Got praised for GPA related achievements which reinforced their over studying/thinking behavior, which leads to the scenarios the author describes.
The most successful people you talk about likely wouldn't have the issues the article addresses.
Browser development is the worst. Hacks and compatibility details galore. I hate the fact that to get into front end development I would have to master how to get around someone elses mess.
You're less likely to get stuck and give up because they're adjacent, and then when it comes to learning something not adjacent you're already a more experienced at learning and organising your thoughts when it comes to tackling a new problem.
I found myself having to look up syntax and idioms of languages I was productive in a decade ago.