Is it really? What about templates(as in C++ templates), macros, CSS and HTML? These are two examples of metaprogramming and two DSLs respectively.

> However, languages like Clojure and Smalltalk can be rather easy to learn, and they are fairly powerful.

It's not like I don't believe you, but if this is true, then where's the popularity? Why isn't it there? I'm asking because I genuinely don't know.

EDIT: punctuation.

"Lisp macros" go far, far beyond "C macros" ("preprocessor macros", and indeed go far beyond what you can do with C++ templates. You should take a look, but basically, explained in a few words:

In Lisp, code is data. Code is a first-class citizen. The functions and constructs that are there to manipulate data, also manipulate source code with the same easiness. So your code can manipulate code very, very easily. Writing code that creates code "on the fly" -be it at compile time or at runtime- is not only possible, it is also very easy to do, and it is 95% similar to writing regular code.

Thus, Lisp is sometimes described as "the programmable programming language."

>It's not like I don't believe you, but if this is true, then where's the popularity?

"Programming is pop-culture" -- Alan Kay.

The reasons a programming language gets highly popular is not always related to the quality of it. There are also other reasons. Consider Javascript for example. Before the ES6 specification, it was plainly a horrible programming language, full of pitfalls and missing features. You couldn't even be sure of the scope of the variable you just declared!! But it went popular, simply because it was the only programming language usable on all web browsers.

C, for example, was never a great programming language. But it ran efficiently on any hardware, so it started as a (very good) alternative to assembler. And then got more traction.

Then object-oriented programming got popular, because it allowed you to do nice stuff (on the Smalltalk language, where it was very well implemented). So somebody said: ok, i want C with object orientation, and C++ was invented, which wasn't a very good object oriented language, but since C was popular, and OOP was the next big thing, it got wildly popular.

C and C++ languages require you to manually manage memory, unlike in Smalltalk or Lisp, where the memory was automatically managed. So somebody at Sun said "ok, let's make a language with syntax similar to C++, but with automatic memory management", and Java was born, and thus, due to the small learning curve, and a LOT of marketing, went wildly popular, although many of the problems of C++ were present, plus it introduced limitations of its own. (I, as a student, loved Java when i learnt it, after having to use C++. How naive i was!!)

And the story goes on and on.

So it's more about riding the wave of popularity, rather than using the best tool for the job. It has also something to do with the triumph of UNIX over other operating systems. Otherwise, Smalltalk [what the groundbreaking Xerox machines used] and Lisp [what the groundbreaking Lisp Machines, and also the Xerox machines used] would be way more popular.

It also has something to do with speed -- Lisp (in the 60s) used to be a very slow language. Smalltalk (in the 70s and early 80s) used to run very slow as well. They also required a huge amount of memory. Nowadays they are not really memory hungry, and they can run very fast.

Some problems are much easier to express in Prolog, or Haskell, than Java or C++ or javascript; but they aren't popular languages. Popularity sometimes is harmful...