Hi Dave! Thanks for compiling this & starting the conversation. So many pivotal moments.
I would add the formation of Cygnus Support in 1989. Cygnus was the first company to offer commercial support for free software (the GNU tools). Renamed Cygnus Solutions in about 1997, it was purchased by Red Hat in 1999.
Great article! Another great one is OpenHatch at http://openhatch.org