Politicians don't tend to like line closures for a number of reasons:
1. Politically very unpopular, even with people who don't use the train.
2. The closures of the 60s and 70s never saved as much money as was anticipated.
3. The process of closing lines and stations is hugely time-consuming and expensive.
Politicians like measures with immediate short-term benefits. Measures which are very expensive and unpopular in the short-term, and where any benefits are entirely long-term? Not popular.
Additionally the current government want to look like they are investing in the north of England having won the 'red wall'. Closing northern railway lines wouldn't play well to the gallery, particularly given the perception that the north was unfairly targeted under the tier system last year.
Whilst anyone can argue that a line should be closed if they want, it's unlikely that the government will agree barring a total economic collapse or a total collapse of infrastructure as referenced upthread.
BR spent the period from 1983-89 seeking permission to close the S&C when it had a whopping total of one intermediate station and a skeleton service. The government refused permission. The signalling upgrade in the 2000s (admittedly for freight traffic which has subsequently reduced) and that no questions were asked about the cost of repairs at Eden Brows indicate the line's future is as safe as it realistically could be currently. Any catastrophic infrastructure collapse might change that, but then the same could be said of many routes.
Does the S&C run at a loss? I assume so, but then large swathes of the network do. The routes BR designated as part of the Intercity sector were chosen in part so that sector could be seen to run at a profit.
Is it a 'basket case'? If it is then large chunks of the railway could be described as basket cases. There are likely plenty of routes running at a worse loss. Whilst it does have some expensive infrastructure such as Ribblehead Viaduct and Blea Moor Tunnel, 2 hourly 158s running at 60mph presumably can't cause that much wear and tear to the track. Whilst freight will, freight is supposed to pay its own way to a much greater extent than passenger rail. The regular steam specials in normal times also presumably pay their way. On the other hand, this document indicates there are 9 open signal boxes. I presume the cost of staffing them would be a significant part of the line's costs, although I don't claim to be an expert.
Should the S&C be a low priority in emergencies such as the pandemic? Yes probably. Northern should focus resources on its busiest routes unless there are good reasons for doing otherwise. In normal times a 2 hourly service seems about right to me.
