Automating a datacenter is trivial. 19-inch standard racks made to hold boxes in multiples of "U" height. All you need is standard power and data bus points to avoid having to do custom wiring. Robots can easily slot in units or racks. Just back up an automated truck to the loading dock 2 or 3 times a week to deliver automatically-built new units and haul off the dead/obsolete ones to be disposed of.
A data center is a bastion of clean, easily accessed, regular layout, and computers are good at handling consistent and repeating patterns.
On the other hand any manufacturing industry location is the complete opposite - non-regular layout, abundant dirt and grime and all manner of inconstancies built on layer and layer of previous versions. If you wanted your typical manufacturing plant to be able to be serviced by a remote unit, you would have to tear it down and build it back up from scratch. And that is not economically feasible - unless you simply just scrap manufacturing in the US and build shiny those new plants from scratch in the $CheapLocationDeJour (did anyone say Africa????)