I work in the rail industry on the infrastructure side. As such I get no discount on train travel (nor do I expect one!), nor does the company I work for have any incentive to use rail travel over other modes, although it is encouraged for environmental reasons - provided the cost and time is similar. My job regularly requires me to travel extensive distances across the country, and from a leisure perspectives I occasionally have weekends away in cities around the UK.
I live in a semi-rural village which has a poor bus service that connects to the nearby town with a station but does not actually serve the station itself, requiring a 1.5 mile walk. Realistically I therefore need to use my car to get to the station. Despite this 6-7 years ago I would happily catch the train to get to my meetings and even some site visits as I knew I could spend the time productively working, get a cup of tea from the trolley and enjoy the experience. This is on a regional service, not InterCity.
Since COVID, the journeys I have attempted have been far poorer, with less seating available and therefore less chance of a seat (and therefore my ablity to work), the virtual withdrawal of the guard into the back cab meaning that anti-social behaviour has increased, and the removal of catering facilities. There are also plans afoot to change the service meaning I would need to change, thereby making me less productive.
In contrast, I am able to get into my car (which is paid for, insured and taxed anyway as it is essential to have where I live) and drive to the same offices / sites in either the same or considerably less time than the train, in comfort. Even using personal mileage expenses rates this generally works out cheaper than the station parking + rail ticket. I am able to change my plans easily, go to a different site if necessary and have ample space / storage for PPE and tools & equipment.
For leisure travel it becomes even less financially sensible, and if taking more than a small suitcase its frankly a pain, especially where changes of train are required. I generally expect at least one cancellation or major delay en-route now, which means we lose time at our destination and we end up with a fractious child to entertain whilst we wait for the next train, often on a cold and unwelcoming platform.
Unless rail travel becomes better value, has a better on-board experience than a car, or is significantly quicker why would I ever go back?