I have been in I.T. for over 30 years now, and what you describe in your article is an example of a general trend that I have observed over time, and that is that roles are becoming narrower and more specialised.
In the early days, I.T. people tended to be generalists who knew a bit about most things, and would learn what they needed to get a job done. It was quite easy to move from one role to another, and employers did not demand a list of very specific skills as long as your arm before they would even interview you.
Now, although there are a lot more people employed in I.T. it is much more difficult to move roles because employers want you to have experience in all the tools, apps and techniques they are using. You can be rejected because your experience of a given product is not on the version of it that they are using, even though your domain knowledge of their business area is strong. (This has happened to me.)
Another downside to the role-narrowing trend is that people have less understanding of the roles and processes that interact with their own work. That can lead to decisions being made where the impact of that decision on dependent or related processes is not considered.
So whilst it does mean you can focus on one particular thing, it is bad for future employment prospects, and can have an impact on harmonious working.