In the typical mid- to small-sized manufacturing plant (and similar facilities), the maintenance crew is just barely enough to satisfy the demands of maintaining the production equipment. Management takes for granted that the service transformers, service switchgear, service power factor correction capacitors, main power switches, service panel breakers, and main feeders from the service are, and always will be, in proper working order.
Maintaining these items requires several specialty skillsets plus special test equipment, special tools, and special PPE. It is rare that any mid- or small-sized manufacturing plant has even half the test equipment needed to properly assess the condition of their feeder cables, much less these other items.
What about all the distribution transformers, panels, breakers, and conductors? Typically, some maintenance is done here with a combination of visual inspections and DMM readings. Some of these plants may have a power analyzer, harmonics analyzer, or other more advanced test equipment but they often fail to provide their personnel with the training needed to fully leverage that equipment investment.