From that thread:
Forestry was already pretty much abandoned.
The switch to a visible source model is largely an attempt to breathe new life into the mod and bring some new people in to help maintain and improve it.
If there is no one out there willing to contribute to the project, then it might as well die.
However, there is no need for anyone to "take it over" because the current project is setup so that such people can help maintain and improve on it as it currently exists within the framework of the ForestryMC project.
If someone comes along with the drive to work on it, a compatible viewpoint, and proven skill, I'm sure they would be readily accepted and given commit access. It happened to me and several others after all.
That was covertJaguar, one of the contributors. Did not make for optimistic reading for me