For clarity, I absolutely meant this distinction.
I understand that someone operating an electricity distribution network will want remote access and yes it will probably cost more money to tie something together without using the internet than using the internet. I understand also that someone might make one decision for end-user meters and a different decision for other parts of the network. (At this stage I am unsure whether the end-user meter at my place represents more of a security risk to me than the other way round. )
At the same time, some parts of the organisation may be on the internet, hence the need for and inconvenience of an air gap.
If the business reasons are overwhelming to put critical infrastructure on the internet, I suppose the question would then arise: what do companies need to do in order to make that acceptably unsafe given the clear and present danger?
In some countries the government is going to take the decision out of your hands. There is clearly a national security element to this discussion and that may overrule cost considerations. Countries that prioritise cost may be at a disadvantage were hostilities to break out.
However obviously you have the real sector experience, so feel free to expand on anything.