Some train companies have reached settlements to avoid legal cases which they would have lost. Unfortunately the details are not able to be disclosed on the forum, at least not yet.
There have also been some
nearly cases such as this one
https://www.railforums.co.uk/threads/taken-to-court-facing-criminal-charges-advice-needed.156920/ where the OP was being incorrectly threatened with prosecution by TIL/XC, despite having a valid ticket. A forum member who is a solicitor was prepared to defend the case
and then pursue XC for damages for breach of contract, and a company director was prepared to be an expert witness if required. But the OP instead decided not to take up the offer (which was at no cost to them) and instead paid a four figure sum to a company who did not pursue XC. At the time, someone who worked for XC admitted to me that they hoped the matter did go to court because they were dismayed at how their prosecutions department were behaving.
The biggest problems are that a lot of people are very keen to avoid matters going to court, even if they would win, and the costs are not small, with very little to gain.
That said I do have an inkling that certain train companies won't get away with such breaches forever.