But there are high end applications where companies are willing to take that hit. OpenVMS is used in some nuclear power plants. When you have data coming in from tens or hundreds of thousands of sensors, and processing that data is vital to keep things from exploding, you want something that can process it all in real time and never crash.
BASF's STOP is another example of a very specific purpose operating system geared entirely around security.
Are you familiar with the instrumentation on nuclear plants? I can’t imagine there are high tens of thousands or hundreds of thousands of variables let alone sensors to be monitored. On the hydro plants I work on there are about 1000 variables per turbine generator unit and another 1000 for the substation and river system that are centrally recorded.
Yes, but that doesn't have much to do with hobbyist or student licensing, does it. If you are an energy company you probably have some sub-sub-sub budget line somewhere for 'computer license' stuff.
BASF's STOP is another example of a very specific purpose operating system geared entirely around security.