Are there actual examples of one TOC making savings by taking a chunk out of another TOC(s)?The primary fare setting will all take place within GBR, who will also be responsible for ensuring that any fare setting sub-contracted to operators is defined so as to not undermine the overall structure. Politically it will take a while to bring some logic to the overall structure but there should be a fairly early objective to address the worst through-ticketing rebooking anomalies - and in many cases where the flows are non-core the sensible approach will be to eliminate the higher of the conflicting fares.
It's very hard to over-emphasise the degree to which large parts of the fares structure have really had no effective overall control in the franchise structure. Accepting (as the Williams-Shapps report does) that a central body needs to be accountable for revenue is a major step given that the ideology of the 1993 Railways Act was that there would only be light touch overall control and things would somehow magically resolve themselves out.
The constant slating of ATOC/latterly RDG when that function was only ever engineered as an emasculated hub designed only to react to either member operators or DfT shows how the vacuum of leadership has been missed in the commercial sphere.
There's no guarantee, but there is now a framework for it to be a possibility.
The overall structure has been in the deep freeze for 25 years so is ripe for massive updating. Savings created by one TOC taking chunks out of another can't be sustained but frankly the ludicrous overpricing of many marginal flows won't get the industry past Covid either. Remember that the main driver for pushing fare levels upwards rather than using real market insights to spot elastic markets that generate more revenue with lower fares is the Treasury so prising away day to day management of rail industry commercials from Government whilst leaving it in a publicly accountable body is the only way the current impasse will be broken.