I think this was a very well written piece on the real-life issues facing a development team (be that open source or behind a corporate firewall). I also think that calling all of these points "myths" is worthwhile. The real problem with myths is not when people choose to believe them with their eyes open, understanding what the pros and cons are. The real problem is when people believe that the "myth" is absolute truth and give it no further thought.
The successful development teams out there have undoubtedly figured out the distinctions the author is trying to point out. This article is not for them... It is for the rest of the people who have not yet "skinned their knee" on one of these "myths" and learned how to avoid the problem in the future.