[spauldo]

A Linux-based system would be identical to a Windows-based system as far as operator experience goes. They interact with HMI software and only see the OS underneath when Windows pops up silly notifications and errors.

Windows owns the industrial space for historical reasons, mostly to do with OPC being Windows-only and software for doing maintenance on field devices originally running on DOS. It quickly became a chicken-and-egg situation - everyone wrote their software for Windows because everyone else wrote their software for Windows. SCO owned a decent chunk of the field before that, but we know how that worked out.

We're seeing some change now that OPC is being phased out. Ignition now has feature parity between Linux and Windows (barring OPC, of course). Windows won't go away any time soon (if ever), but you can now have a fully functioning SCADA system with no Windows at all.