Contemporary web development processes and tooling enable website developers to create phenomenally rich, complex, and beautiful websites without ever needing to learn the fundemental technologies on which they are built. With over two decades of development and market survival, content management systems (CMS) like Drupal and WordPress have evolved to the point of themselves being considered a minimum starting point for website development, obfuscating much of the underlying technologies on which they're built from new developers.
Further, entire frameworks for higher level design are now mainstream, like the Divi integration for WordPress by Elegant Themes. Divi itself supports an entire ecosystem of Divi compatible sub themes and plugins further abstracting away the need for a new developer to learn more advanced fundamental web development technologies such as CSS and Javascript.
This is similar to trends in software development with new languages and language frameworks being developed on top of predecessor technologies over time to help expand the capabilities and potential productivity of a developer. And as with software development, I believe that it is important for website developers to learn about the fundamental technologies and their core principles of utility in order to better understand the higher level CMS and similar website development tooling they're using.
Success is neither magical nor mysterious. Success is the natural consequence of consistently applying the basic fundamentals.~ Jim Rohn