Whilst I agree with the bulk of your point, there is some through traffic Leeds-Lancaster. Not much, mind, but some - so there are more than 50 passengers a day using the line. Maybe a couple of hundred in non-COVID times?
Leeds - Lancaster is around 1h50 direct
In comparison, Leeds - Preston is around 1h45 direct and Preston - Lancaster is around 15 minutes, so you could do Leeds - Lancaster is slightly over two hours with a good connection at Preston (given that Leeds - Preston is hourly and Preston - Lancaster can be three or four trains each hour)
Or Leeds - Manchester is around an hour and Manchester - Lancaster is around an hour, if you want to go that way.
So it's not a significant increase in journey times for those longer distance passengers (and, not all of them are obviously heading to Lancaster itself, so may be changing to services for Windermere/ Barrow/ Penrith etc anyway, which makes a journey via Preston less disruptive than may first appear to be the case)
If you're looking at the costs and benefit of a route, then you have to take into account of much more than just revenue in the "benefits" column. That includes all of those benefits to society that you tend to describe as "woolly"
These unquantifiable "benefits to society" are described as "wooly" because they are always relied upon to distract from the fact that very few people use a station/ service/ line - if you have three stations with half a dozen trains a day in each direction but only around fifty departing passengers then you'd struggle to run a minibus with such low levels (and heavy rail obviously has significantly higher costs)
In the example of the Little North Western, you cite the passenger numbers from three intermediate stations - Wennington, Bentham and Clapham - what's the justification for missing out Giggleswick out of interest ?
Giggleswick station serves a couple of houses and a pub on the outskirts of Settle.
I'm pretty confident that if you closed the station, the vast majority of the current passengers would just use Settle instead (the station in the centre of the town, rather than Giggleswick, which is pretty inconvenient for most people)
This clearly ignores the use of the line as a through route. And you can't justify that omission by saying "oh you can use other routes"
As mentioned above, the time penalty for going via Preston is pretty small over a two hour journey
I travel regularly between Yorkshire and Lancaster and have had cause to use all routes due to Northern's lockdown timetables and strikes etc. The missing through trains via Skipton cause me real issues in getting between the two and theit benefit isn't easily replicated by a long and winding alternative route
It'd be a five/ten minute increase in journey times from Leeds to Lancaster (less if you are heading to Windermere/ Barrow etc)
Saying it's cause you "real issues" sounds significant, but we're just talking about a mild inconvenience on leisure trips, right?
Similarly with Sugar Loaf Mountain. If the only people who use the Heart of Wales line are the one person a day from that stop, then you may have a point, however that's clearly not the case, so I don't see how this amounts to an argument against the route
It's a station that barely gets any use - yet you still can't accept closing it - there'll never be a station with passenger numbers pathetic enough for you to accept it doesn't warrant a heavy rail service
In terms of costs, we have a situation where the railway is lumbered with an ongoing revenue payment for rolling stock whereas previously once the initial cost has been paid off, the railway would have had depeciated rolling stock to use for just the maintenance cost. That is a cost that has been created purely to satisfy the free market idealogy of privatisation and I see no reason whatsoever why this cost should be prioritised over the running of the passenger network. This is an example of a cost issue that should be resolved instead of contemplating passenger closures.
Under any twenty first century organisation, you have assets and prices associated to them. Given that the Government got money when it sold the trains to the ROSCOs, they are recouping that money.
But, as usual, you're trying to move the goalposts. Even if the trains were provided by the ROSCO for no cost, you're still paying for drivers/ guards/ track maintenance/ signalling/ insurance etc - fifty passengers a day probably aren't covering the cost of one driver's wages yet alone all of the other costs.
The reason that the Bentham line is being discussed isn't because the ROSCOs are charging for use of their assets. The reason that the Bentham line is being discussed is because the passenger numbers are so low - blame privatisation if you want, blame the free market, but there's no getting away from the fact that the three stations in questions (with around half a dozen trains a day in each direction) don't have combined passenger numbers to fill a single 153.
Sorry, but your logic here really doesn't make sense. It is sensible financial practice to depreciate an asset over the full duration of its useful life, not to depreciate it over the profitable 75% of its life and then pretend that it's free for the final 25% and use it on an unprofitable service. All that's doing is hiding the rolling stock cost for the branch line in the accounts of the main line. I'm not saying that unprofitable lines should close, but it is definitely wrong to pretend that they are less unprofitable than they actually are.
I think Rob would like it if we fudged the figures so that we didn't have to count any of the awkward bits (hence the idea to "hide" heavily loss making services in the same set of figures as busy/profitable InterCity services, so that nobody notices the subsidies required to maintain the likes of the Bentham line)