The Debian design process is open to ensure that the system is of the highest quality and that it reflects the needs of the user community. By involving others with a wide range of abilities and backgrounds, Debian is able to be developed in a modular fashion. Its components are of high quality because those with expertise in a certain area are given the opportunity to construct or maintain the individual components of Debian involving that area. Involving others also ensures that valuable suggestions for improvement can be incorporated into the distribution during its development; thus, a distribution is created based on the needs and wants of the users rather than the needs and wants of the constructor. It is very difficult for one individual or small group to anticipate these needs and wants in advance without direct input from others.
This amazing quote from 1994 (!!!) actually models the way I think about software engineering at Parse.ly.
A nice piece of nostalgia on Debian’s 19th birthday.
See also: A Brief History of Debian, The Debian Policy Manual, & The Debian Developers Map.