I really think that, to try to make a point, you over-egg the Scottish situation.
Since privatisation there's been...
- the Larkhall branch (a short stub)
- the Alloa branch (a short stub)
- the Newcraighall branch (a short stub)
- stations on the short section of line from Queen Street to Anniesland (effectively a short stub, given that the DMUs operate independently of the EMUs at Anniesland)
- the extension from Newcraighall to Tweedband (which only happened due to horse trading at Holyrood - the price that the LibDems wanted for going into coalition with Labour - a line built after significant delays and significant cost increases that has met expected passenger numbers on some stations and failed to meet expected passenger numbers at other stations)
- money is being found for the Levenmouth branch (a short stub)
...there seems to be this idea from enthusiasts south of the border that Scotland is a land of milk and honey when it comes to re-openings. Instead, things are pretty modest, and the circumstances of the Borders re-opening are never going to be repeated any time soon (younger readers may be scratching their head about the idea of a Labour-LibDem coalition at Holyrood...)
So, your argument is that spending the money on longer trains would be a better benefit (than reopening an old line) and that spending the money on road improvements would be a better benefit (than reopening an old line)... but that we should spend the money on reopening an old line anyway because it's better to benefit a handful of people who don't have a train service, rather than bring about quantifiable benefits to a much larger number of people?
It's almost like you start from a position of "we need to reopen some old line" and then work backwards to try to find a justification.