Front end dev/JS interview: topics like prototypes, context/scope still needed?

I'm a frontend dev for more than a decade, and constantly interview new developers for 5 years. In my questions I always tried to avoid framework-specific questions and - in the JS part - lead conversations to mention basic and newer concepts like scope, context, browser event handling, closures. These are things that come up with literally any google search on "frontend interview questions". But. In the past few years, but also overall, I get really bad or very basic answers. Senior devs clearly having many years of experience could at best give partial and mostly incomplete answers.

It really disturbs me why, and can't find a cause for it. We could say we just got bad candidates (I worked for 6 companies in 2 mid-european countries, positions were with average/good salaries and actually interesting work, not agency stuff). Or maybe that devs are so high in demand that they just don't prepare for technical questions (I'd say in all my interviews maybe 20% had any serious technical part).

But then it occured to me how little these basic language features are used nowadays directly. Prototypes are abstracted away for good, classes are mostly present as built-in elements. Frameworks (and thus devs in general) use "this" less and less (thank God). Componentization removes the need to think about bubbling/capture. Conventional tasks can be solved without "smartass" array functions that are not map() or forEach(). I'm not even mentioning "low-level" mechanics like the event loop. Frameworks and proliferation of a few basic patterns erased high level concepting like design patterns or phrases like higher-order functions from most dev work.

I still believe that these concepts are basic and you're flying blind if you don't know these parts of a language. But yet I see how seemingly able professionals stumble at these questions. How could basic concepts be explored better? What is your view on a swift and fun real-world-based FE interview?