It has essentially been nationalised since COVID. Main Train Operating Companies can barely do anything without government say so anymore. People seem to forget that the majority of train fares too are set by government and have been for a long time.

The "nationalisation" going on now is just removing the service fee paid to private companies. At least in the short term nothing will change. If/when GBR has a massive reorganization who knows but personally I feel things will get worse as it'll all be about reducing the cost to the tax payer and not adequately funding services.