I would classify things like NFDB, or any large infrastructure as application specific.
An AS system is usually not useful to anyone except the people it developed it, and the problems it solves at that place. Those usually require hitting a certain scale (one that is low or high depending on the type)
Anyone else that has a similar problem will not be well served by someone else’s AS system, as “similar” is not enough. And they usually have the skills to build their own.
The only people that benefit from open sourcing such a system is people that want to rip off existing effort for a quick buck and don’t care how well it runs or fits them.
For the average user, there are the standard options, that work much better at their scale.