I walked the factory floor in the manufacturing end of a large international corporation on Tuesday of this week. We're assisting them in a significant facility renovation. All of their data collection, shop floor tracking, timekeeping, etc was and had been wireless for quite some time. No wires, cables, fiber - except to transceivers and they needed no attention.
In my prior life (5 yrs ago) for another large firm there were some wireless machine control and process monitoring systems that we used quite successfully. There were some timing issues but we had those with hard wired (to bus) systems too. Keep in mind that a machine in that place could be 300 ft long and 4 stories high. Materials transferred to/from might be several thousand feet away.
So, "some" and "many" is a good description.