Back to the subject!! I would suggest that part of the issue is that a good proportion of rail fares, especially long distance are in some way paid for by an employer either by means of a loan for a season ticket or by way of expenses for single trips. Thus some rail companies price not so much by cost per mile, but by cost based on the type of user. To illustrate this, I live half way between Cheltenham and Evesham. The same company, First Great Western, is the only company that runs trains from these two stations to London. The return fare for the train that gets in to London just before 9.00am is nearly double if I go from Cheltenham!!!! Not only that, but you have to specify which train you will return on. From Evesham, you can return on ANY train! Cheltenham is clearly a better market and therefore people can pay more! The journey time is almost the same, but going from Cheltenham you often have to change at Swindon or, later in the evening, Bristol Parkway, a god-forsaken location at 10,30pm! From Evesham, there are more direct trains! The only real gripe is that because there is no competition, you can not get a cheaper fare no matter how far in advice you book. My colleagues who live close to the East Coast Line can get cheaper tickets as there is some competition between the rail companies coming in to London, however again they have to catch specific trains.
On the subject of Split fares, if I go to Birmingham from Cheltenham or Tewkesbury, I get a split ticket at nearly half the price.
Anyway, I wouyld agree it all worked much better when there were steam trains!!
Phil