The 10x seems to mostly have been from programmers switching from extremely low level languages like C++ to something far higher level. Paul Graham also talks a

The 10x seems to mostly have been from programmers switching from extremely low level languages like C++ to something far higher level. Paul Graham also talks about macros in his well known essay, but I honestly think a lot of the value one gets from Lisp can be found with Python. There are a lot of things you don't have to worry about like manual memory management and so on. Python isn't as fast as lisp or as beautiful (opinion), but the ecosystem is very impressive and the community isn't as fractured as the lisp community (for example see the bipolar lisp programmer essay). I don't think FP by itself is that massive of a win despite what some dubious studies or zealots say, but it's certainly better than enterprise Java. I've read my fair share of horror stories of Haskell in production too.