Industrial IOT is mostly secured through network segmentation. There is a lot to hate about this fact.

However, by career I deal with a lot of embedded devices. Embedded is where the hell begins. Embedded plus standards is pretty bad. SCADA and others. Embedded plus standards plus vendors .. now you are doomed. The half-assedness of embedded systems security is worse than any normal coder can imagine.

Basically the IIOT domain is the one place that remains where network segmentation and encirclement and so on are the only things we have that work. The worst best option.