[tel]

One reason is that it actually is just layers and layers of nested code. While that sounds troubling as written it's a relatively simple substrate for writing code in.

I'm not certain that it is the trending language, however. Many "advanced" functional languages are trending nowadays. These languages tend to include some subset of fast functions, good modules, strong typing, pattern matching, good support for concurrency, generics, higher-kinded types, ubiquitous HOFs, easy lambda syntax, abstract data types, immutability, lack of exceptions, encapsulation of effect, minimization of state, so on and on and on.

Clojure is one of these remarkable for its (a) lisp syntax (b) dynamic typing (c) well-spoken leader, and (d) austerity.