Earlier quoted context omitted.
Knowing basic web technologies to a deep level are very important and highly valued, especially so at larger companies where they know that the framework itself is a minor detail for skilled engineers who can pick up and be productive in any framework in less than a weeks time, so I do think you can command high market value with very deep knowledge of the platform itself. However, that said I agree with you. Especia…
Lots of reference in these comments to "core" or basic Web technologies. What would you say they are? What's the highest-level thing that's still "core?"
I never mentioned build tools. You can write your own quickly.