There is an inescapable connection between the two. Knowing that stuff is not _equivalent_ to knowing good architecture, but it's hard to imagine what knowing good architecture would look like without being able to "think in code" through quite a few relatively narrow implementation details. Without that, you won't know the shape of the problem and how to architect around it.
I'm not sure skill loss is such a huge issue, in other words. It might just be a sign that the nature of our work if shifting. Being able to recite the C++ standard and using all the 100s of features correctly will just not be as highly regarded as knowing good architecture instead?