We in the open-source community have learned that this rapid evolutionary process produces better software than the traditional closed model, in which only a very few programmers can see source and everybody else must blindly use an opaque block of bits."
Note that GNU was initially a reaction to the closed source code of the AT&T UNIX days. With the advent of open source code for Berkeley UNIX such as FreeBSD, that need is diminished. Perhaps the greatest constibutions of GNU are the widely popular and platform-ported free GCC and G++ C and C++ compilers and development tools, the GNU Emacs editor/environment, and the distributively-open Copyleft distribution paradigm and accompanying free software philosophy.