And then there are models which are not useful at all (emphasis mine):
“consider an all-OSS world in which each company offers consumers exactly the same shared code as every other company. By definition no company can then compete by writing more OSS code than its rivals. This lack of competition suppresses code production for the same reason that cartels suppress output.”
Or to put it in other words, because companies compete within a common code base, they contribute less and less code into the project because they run the risk of losing a future contract to a competitor using code they have submitted.
The authors of this study are advised to read the history of the X Window System whose development closely follows their model. X is universal in the Unix world (commercial and open source systems who try to converge by being POSIX compilant (another hint here)), never faced lack of contributors and contributions or even stewardship and whenever stagnated new branches forked and pushed it forward. And while the authors seem to think that Open Source has been with us for the last 20 years, X was born in 1984. In fact we’ve had Open Source software since the very beginning of software.
Update: After this post and a discussion on twitter, Gregory Farmakis performed a mind experiment.