That's a good question without an easy answer, but there are two leading theories. One is that languages are infrastructure and it's really hard to replace inf

That's a good question without an easy answer, but there are two leading theories. One is that languages are infrastructure and it's really hard to replace infrastructure once it gets established (look at how much time it's taking for electric cars to replace gas-powered ones). The other is that Lisp's productivity boost allows individuals to get things done by themselves and so it tends to attract people who aren't good at collaborating (the famous "Lisp curse"). So on an individual level it's a win, but at an organizational level it might not be unless you manage it very carefully.