Was the Intel 186 chip commonly used anywhere? Was it only found in industrial computers? Why not PCs?
There was an actual PC (somewhat compatible) computer built with the 80186.
That was the Tandy 2000 from Radio Shack.
I have vague memories of being envious of the better graphics it had over the Tandy 1000 my family owned at the time.
From all that I have read, it wasn't fully compatible with the IBM PC.  It did run MSDOS, and many of the commonly used programs were available for it.
The Wikipedia Tandy 2000 page refers to a second computer that I'd never heard of that also used the 80186.
That's the Mindset.  It had better graphics than the Tandy 2000, and a MOUSE.  It was apparently, though, even less PC compatible than the Tandy 2000.