GWT was a solid platform for quite a large number of years, and is still used in quite a large number of enterprises. Also, there are a lot of good ideas in there that the JS community is only just catching up to, like dead code elimination.

A lot of modern javascript/typescript syntax is inspired by CoffeeScript. And CS is so trivially easy to learn that "saved a few brain cells" sounds like intellectual laziness.

There's a fair argument to be made for not jumping on the bleeding edge. But your examples are all mature technologies that had good solid lifespans during which people used them to build successful products. If those are fads to you, I'm guessing you must still do most of your work in C?