Yes, it's an essential service.
And yes, this gives extra leverage.
We used to have many essential services run by the gvt. - Royal Mail, railways, utilities...
(not the buses, but there were lots of small and large bus companies, as we discussed recently).
Then they were privatised.
Co.Durham has been exploited for its minerals over the past couple of centuries. These minerals, particularly coal, were the reason it became the cradle of the railways. Darlington built locomotives until Beeching closed down the line the locomotives needed to use for delivery, and was also known for fabricating large bridges. It even had Patons, who made knitting wool, a remnant of its past, which used to be based on wool.
Shildon's wagonworks, Consett steel works, Wolsingham and Tow Law foundries hung on as long as they could, but the iron had run out and there was no longer any call for wagons.
.
This left a substantial population - which had only come about because of the coal industry - with no employment. To the West, for a while, the men had to rely on the womenfolk earning a living in the clothing industry - eg Burberry in Crook, Charnos in Peterlee who made clothes for M&S.
The coal industry hung on in the East, where the mines were deep, but there was still coal. Until Thatcher decided that unions were a bad thing. Next year is the 40th anniversary of the last miners' strike.
Now Co.Durham has some car assembly, some other relatively small industries, a University, a small tourist industry, a few gvt departments like Passport and Student Loans (if they are still in Darlo), selling things to each other, and a service industry.