I think part of the problem is that the statement above is maybe not as true as it used to be.

Let's stick with Python as an example, though it's far from the only culprit so I hesitate to single it out here. I have a growing list of areas of the standard library that today I just assume won't work acceptably. I have tried to use them before, and I have found them to be either bug-ridden or not robustly portable or so slow as not to be worthwhile or missing enough basic functionality that you need to add something else anyway or just write everything from scratch. The everyday stuff in Python is pretty good, the basic data structures and common supporting functions like itertools, but when you start getting into the less common areas I have a very low opinion of the design and quality of the Python standard library, and that opinion is born of direct personal experience.

On top of the quality and robustness, there's also usability to consider. Even if some of Python's built-in libraries do work, there might be much neater, easier ways to achieve the same result that are only a `pip install` away. Libraries like Kenneth Reitz's Requests come immediately to mind; if I were teaching a newbie to program Python tomorrow, somehow I doubt urllib[N] would feature much.

I'm not sure how that hypothetical newbie is supposed to discover these things today without someone experienced to guide them, though. Whether it's Python and PyPI or Perl and CPAN or C++ and Boost or whatever other language and library repository you like, there's a lot of collective wisdom about the easiest/safest/fastest ways to get things done, but it lives in the combined experience of veterans rather than in comprehensive tutorials to follow once you've got the basics down. And that's only when there is already a recognisable place to look for general use third party libraries, not even considering all the third party libraries that might be out there but for whatever reason aren't incorporated into any de facto standard repository to make discovery (relatively) easy if you at least know what you're looking for.

Is it any wonder that newbies reinvent wheels under these conditions? It seems almost inevitable to me.

I taught high school for a while, and I had kids that refused to stop using their fingers for addition, regardless of the fact that it was preventing them from learning how to do more abstract math. What you're describing is pretty much the same attitude.

Join the club. We're getting T-shirts made. :-)

The thing is, in those days we really could learn all the commands of an operating system shell by reading the manual cover to cover in an afternoon, or play with graphics demos or write low-level system utilities after reading the Pink Shirt Book.

Today's systems are so vast and complicated that anything offering similar coverage in book form would be the size of an encyclopaedia, so the way we were able to learn doesn't scale to modern needs.

The trend over the years has definitely been towards writing glue code and joining up ready-made components for a lot of professional work rather than reinventing things from scratch, and in some ways that's no bad thing. However, I think it only works if you know what you've got available in your toolbox, and so does being the person who understands and creates new components. Either way, it comes back to needing a way to navigate the vast amounts of information now available and pick out the bits you need to achieve whatever it is that you're trying to do.