>>40296A"I" systems depend on algorithms to do decision making. You'd need to implement a pathfinding algorithm (e.g. A*), which in turn needs map edits (node network) and/or additional worldspace code (navmesh generation) to work well. It's not that these systems are not known or well understood, it is that implementing acrue compounding costs (first adding the algorithm, adapting the existing systems to work with that algorithm, making changes to the entire game world to ensure they are utilized well, and finally bug- and playtesting). This is referred to as overhead, and why direct sequels are often more nuanced/content rich than their predecessor (less novel complexity, thus less overhead). Relevant to Outer Worlds as that was Obsidian integrating their own world and NPC systems with UE.
Same goes for a task system. First the abstract of these tasks need to be implemented (log, schema, etc.), connected to the world state (time of day, weather, location), concretised into actions (pathfinding, playing animations, leaving and being deleted from the worldspace), and tested.
Again, I can not stress enough that all of these individual steps are known, but that they cost time to implement and test and thereby incur overhead. Obisidian, for whatever reason, decided not to allocate resources in that direction.