I think you're trying to make excuses now

It wouldn't cost that much compared to the revenue. To some approximation, all you'd need to do is allow charging authorities access to the information that I believe modern cars already record concerning where they are (and there would be beneficial side effects too: For example, you'd likely see a massive reduction in levels of crime that involve motor vehicles, because the police would immediately be able to tell which vehicles were involved in the crime).
Up until recently (i.e. before technology made it much easier) trying to build toll booths would have been vastly expensive.
Even TfL (using cameras) don't actually keep all that much, total net received about £110 million from receipts of £259 million from ULEZ and £233 million (there are other road charges) so at best less than 23%.
One of the reasons so many people drive is that motorists aren't charged for the external costs of driving: Society, including all the non-motorists, pay indirectly for those - and that distorts economic decision-making and resource allocation in favour of cars. Your 'solution' to this distortion appears to be to add a further market distortion by having rail users also not charged for any of the external costs of running the railways. Have you considered that a better solution would be for all transport users (motorists and rail passengers) to be correctly charged for the resources they use? I imagine that if we did that, we'd see a major shift towards public transport (and walking/cycling) anyway. (Which - trying to get this thread back on topic - may well result in an increase of usage of rural rail routes, so we wouldn't be discussing closing them)
Until there's a serious suggestion for road pricing, there's a question of which is likely to be politically more acceptable?
That's not an easy one to answer, however to have a reasonable discussion over the best way forwards it's worth asking the question, what does the public prefer, free to use public transport or further road changing and details of what that would look like.
Whilst they may mean further market distortion at least public transport would be on a more even footing with road travel.
Whilst it still wouldn't deal with the costs of too many cars, it may well reduce the overall number so the outcome is something better, even if it's not perfect.
I've never said that free public transport isn't without it's issues, but then nor is road charging. Ultimately, the point is that free public transport is probably better than the current situation where the use of public transport is discouraged but the use of the roads hardly is.
Err, no. Rail passenger revenue from fares is about £10 Bn/year. Bus passenger revenue adds £3 Bn/year. By comparison, entire DfT's entire spending is £44 Bn/year (
https://www.nao.org.uk/wp-content/uploads/2024/11/department-for-transport-overview-2023-24.pdf) so if you abolished rail fares, you'd have to increase the DfT's budget by nearly 25% just to stand still in transport provision. That is not affordable!
Using that logic, if an individual's fuel costs for their car increased their car ownership costs by 25% they'd need a 25% pay rise. In terms of overall government spending it would be no more than 3.2% (even that is assuming there's currently zero government spending on public transport).
Also, as I've said before there would be other cost savings (including from the DfT budget), and it's possible that the costs of running the railways would reduce.
For example you wouldn't need to retain all ticket office staff to still increase the number of staff on platforms, you wouldn't need any revenue protection staff, the gate line staff wouldn't be fixed in place, the IT costs would be lower (no need to have ticket sakes websites), much reduced transaction costs (due to far fewer transactions), etc.
Yes you'd need guards, and platform staff, but there could be savings.
Likewise without having to touch in and out on buses (let alone pay cash) there's the potential for time savings, as well as other savings (again transition costs).
The only reason I haven't brought that up is that I chose to focus on the economic principles of why free public transport is an awful idea. And there's a limit to how much I want to write in my posts!
The point was more the fact that normally such a suggestion would be put down by several people on cost grounds.