``It may metaphorically be said that natural selection is daily and hourly scrutinising, throughout the world, the slightest variations; rejecting those that are bad, preserving and adding up all that are good.''Charles Darwin, [2, chapter 4]
Doesn't it seem like Charles Darwin is talking about software development with the sources available for Anonymous CVS, with people all over the world downloading and testing up-to-the-minute versions? In general, Free Software developed in the Bazaar model evolves precisely as described in the quote above. Proprietary software, however, cannot enjoy the benefits of the fast turn-around time and the world-wide scrutinizing of every single change to the source code base, so it cannot adapt as easily to the moving targets that users' requirements tend to be. Of course, in either model, changes can be introduced that are disliked by users, but in the Bazaar development model, the influence a user can have in the selection of variants is much higher: not only can she choose a variant that doesn't contain the change, but also she can introduce further changes that adequate the software to her needs. Therefore, the Free Software model is more likely to fulfill users' needs, even though it may demand more effort and involvement from users to do so.
The arguments in this paper are based on my personal experience with Free Software development. They explain some of the reasons why ``once open source software colonizes a niche, it will completely dominate it'' , especially when the Free Software is developed in the Bazaar model. It is not just a matter of good will, politics or philosophy; it's a matter of survival: ``Survival of the fittest'' [2, chapter 4].