Kent Pitman, again
And anyway, the subject line presupposes that Lisp has not caught on. This is like saying that astrophysics or calculus or brain surgery has not caught on because in relative numbers, there might be more people doing other things. The success of Lisp is not measured in the number of people using it, it’s measured in the utility to those people who do use it. Turning it into C (or C++ or C#) to make it more popular would not be success. In the world’s menu of computer language options, we don’t need them all to be Taco Bell.
— Kent Pitman.