So what, not like modern OS are completely bug free
Is this really an issue. There connected to an internal network to provide functionality for another device, e.g the checkout.
I recently worked in a large company that make silicon wafers and they have machines in the fab that runs OS2/2, NT4 and Next. You cant just change production systems because Microsoft no longer supports it, it would cost the economy millions, if not billions. to upgrade manufacturing kit across the world. The OS is not the difficult part, it is the hardware support and applications that run on top of it.