I'll happily bow to Yorkie's definitions (and greater experience) of Yield Management, but I'd suggest that it was always going to happen on the railway, regardless of privatisation.
Thanks, but that's not mine! I just linked to Wikipedia and provided an extremely brief summary. I believe glynn80 and Metroland (and probably others) may be more knowledgeable on the subject than I am.
Whilst the likes of Ryanair/ Megabus (etc) have made a big feature out of it, British Airways/ National Express Coaches (etc) have responded by adopting similar pricing too.
Defining "choices, like splitting" as a good thing about privatisation is (IMHO) wrong, as you shouldn't *need* to split tickets- the "through" fare should be cheap enough not to need any splitting!
Splitting 'needs' to be done to obtain the cheapest fare more and more, as different TOCs have different policies, in effect, the TOCs that have the greatest increases cause tickets that they price to go up disproportionately compared to other tickets priced by other TOCs. If you are unfortunate to be a victim of an expensive TOC, then you need to find tickets priced by a more reasonable TOC, either by 'splitting' the journey into combinations of tickets, or buying a longer ticket that assumes travel by a different route. This brings your fare down and also gives other, more reasonable, TOCs more ORCATS revenue and ensures that the greedy TOCs get less ORCATS revenue. But this is a problem created (or at least made a lot worse!) by privatisation...
For example, I very rarely would buy a ticket
priced by XC, when travelling on walk-on tickets on XC. But if it was still under BR, then the through ticket (such as the York - Brum example) would have been far more reasonable, so splitting may not have 'needed' to be done to make the fare acceptable.