Yes, but the desktop computer is typically attached to a $250k piece of custom industrial automation, the fact that there's 200 hours of C# programming for the HMI/ERP client/label printer/data logger is irrelevant to the customer, it's just a line item next to the PLC/robot programming, raw materials, welding, fabrication, wiring etc. Add some Beckhoff, Siemens or (yuck) Rockwell capacity to your stack - buy a used EK1100 and some IO cards off eBay, download TwinCat 3, and add that to your resume and you'll be able to build B2B products for a lot of places.
There are a surprising number of "controls engineering only" shops, it's not clear to me how that kind of business works out logistically when so much of the software requires certain kinds performance from the hardware and vice versa.
I have a background in embedded and a couple years ago I built a custom Windows GUI for an Advanced Motion Controls based motion system as a freelance project.
Until your post, I totally forgot that I have a Kollmorgen AKD control with a servomotor in my basement. A customer had sent it to me so I could test some custom hardware I designed for them and I always wanted to see if I could integrate it into my GUI project, but got so busy I completely forgot it was there.
There are a surprising number of "controls engineering only" shops, it's not clear to me how that kind of business works out logistically when so much of the software requires certain kinds performance from the hardware and vice versa.