Back to the fundamental economics ...
Unless Dounreay deals a trump card to the line, then the economics north of Tain do seem horribly bad, especially when road transport is superior on speed, and with Wick airport offering direct flights to Edinburgh and Aberdeen.
But I still find myself twitchy about the idea of closure. And it comes down to a problem that is much broader than railways: distrust of any revenue-supported service that is proposed to replace expensive physical infrastructure.
In many cases, the proposed replacement will be unarguably better value than the existing provision. It may even provide a better absolute standard of service. BUT many of us oppose such changes because replacements are so much more vulnerable to slow death.
Removal of physical infrastructure is big news - even if you don't have a local paper that anyone reads, local TV will cover a closure protest and MPs will get interested. But opposition to a 15% cut (on top of the 15% cut last year) - try getting coverage for that.
The banking van that replaces the village branch can call less and less frequently. The "Rapid Response" team of community nurses that replaced the cottage hospital - their numbers can slowly cut over a few years, to the point where the response is anything but rapid. And the bus service that was initially superior to the railway that it replaced - that can thin out and perhaps eventually disappear. None will cause a ripple.
Nothing should be continued "because we promised never to change it". But we do need some way that horribly poor-value physical infrastructure can be retired in return for a meaningful promise of a long-term replacement service.
That promise needs to be something better than we have today - even the "statutory obligation" for a local authority to procure "appropriate" transport turns out to be unenforceable. Politicians are addicted these sound-good promises which turn out to be worthless - but the price we pay is that sensible savings are lost as a skeptical public refuses to believe in the long-term security of anything other than (expensive) physical infrastructure.
We need a form of legislated promise that will deliver what it appears to promise, over the long term - and which can only be reduced or substantially modified by heavyweight public enquiry or another substantial impediment to the salami-slicers. Only with such guarantees can we expect communities to consent to the closure of a poor-value railway service in return for a replacement road service.