Hopefully you agree Lisp is more productive than C++? Lisp is however not quite fast or efficient enough to displace C++ completely, mainly because, like Java and Go, it has a garbage collector. C++ was very much the language in Java's crosshairs. Java made programming a bit safer, nulls and threads not withstanding, but was certainly not as productive as Lisp. Meanwhile Lisp evolved into Haskell and OCaml, two very productive languages which thankfully are inspiring everyone else to improve. Phil Wadler (from the original Haskell committee) has even been helping the Go team.