[hellofunk]

First class functions and lexical scoping have been actively used in programming languages since 4 decades prior to the invention of JS.

[woah]

Mysteriously they gained popularity at the same time that JS did.

[hellofunk]

That is certainly not true, and therefore, not mysterious.

In fact this website, ycombinator, is the result of a nice pay day that Paul Graham enjoyed for selling web service he built in the 1990s using functional programming techniques... and it was not JS.