> I learned C from a couple of textbooks, and C++ (such as it was in 1993) from a book published by the company that sold me the compiler.

You ignored that part of my argument about only the rich world having high quality libraries. What if you'r from India or Africa or even rural America? Now even a poor Indian can solve Hackerrank challenges on his phone. It's not as easy or as convenient but it's much better than his prospects 30 years ago.