Pick 'n place are usually only XYZ fixed-envelope cartesian systems with additional part rotation about one axis. Sometimes the XY is replaced with dual rotary units (SCARA), or XYZ are replaced with delta systems. See https://www.valin.com/resources/articles/five-types-of-indus... for a good overview here. Plugging in cables requires fine and reliable gripping at two ends plus additional degrees of freedom, and a clear path through a more complex motion envelope for access. This generally necessitates a move to arms, which come with additional issues (play at extreme positions, repeatability constraints, higher cost, power and space requirements, non-square envelope, slower motion, etc.) Having two of these work together on a flexible part means very fiddly parallel control of two systems with these drawbacks. Basically it's expensive because good end effectors cost a lot, parallel control exceeds conventional industrial requirements, industrial control systems are purposefully non-standardized, sensors have to be added in an application-specific manner and subsystems prototyped as requirements are identified, and experienced talent is hard to find.