To be fair, recent javascript Frameworks, in particular React (together with Flux paradigm), recent Angular, or Vue, are quite unlike previous frameworks such as Ext or original Angular

Previous JS frameworks in general aimed to play catchups with other more mature languages and platforms to provide things like OOO or MVC models into Javascript. Recent javascript platforms, in particular React, on the other hand, bring in new paradigms into UI building. Some of these are now even feeding back to older mature Platforms such as iOS development in the form of Swift UI. The values of such frameworks won’t disappear by switching to some other languages. And in fact, the lack of these more modern platforms and toolsets will be a major hurdle for other languages making in route into Web development.