Interestingly, the only GPIB stuff I've seen is random 70s and 80s surplus junk instrumentation at flea markets. The kind that even I can't think of a reason to own, with the exception of chart recorders. I might be able to find a use for one of those if I were ambitious enough.
But there were some rebranded PET computers for highly technical uses. I've only ever seen pictures online, and don't see any now. I almost bought one that had a boatload of hardware connected to it for what I seem to recall was some kind of medical application. If memory serves, the seller thought he was selling rights to a gold mine.
Alternatively, I have only personally seen Apple ][, Mac, CP/M, PDP/clone, and Pr1me/clone machines* in industrial use. That's where I got my introduction to the Apple ][, and actually, where I acquired all my Apple/Mac hardware. Most of my Apple ][s had (filthy) homes next to some very (at the time) state-of-the-art CNC machines I had the opportunity to run.
*Also some Japanese personal computer type things I can't identify, and of course eventually the ubiquitous AT clone, ad nauseam. And I almost forgot, the DEC Rainbow.