This is a muddled hyperbolization. These features barely existed (in terms of widespread use) even 10 years ago, but everyone got along just fine, even founded FAANG-scale companies without them, and so on. Yet you're making it sound like if you aren't using them, then you're basically still writing COBOL.

Not using productivity tools is just hurting you.

The commenter very clearly isn't saying you shouldn't use them. And their point had nothing to do with any "sensation of superiority".

They simply meant that -- yes, it is possible to not only be productive, but highly productive without these tools -- and that if you just tried to get along with them for a while, you just might learn a thing or two. For example, if one is even the slightest bit hesitant as to how one would go about resolving one of the issues that the OP asked about, without the help of modern tooling features:

   What do you do if you need to look up the definition/implementation of some function which is in some other file?