Sorry but I don't think that's quite true. A lot of motorists MIGHT be tempted out of their car, if there were a reasonably priced, relatively frequent and reliable alternative. Mostly in the UK, outside of large cities with extortionate parking, there isn't.
To take a personal example, we often travel from Cumbria to Manchester. Yes, there is a train, but it's infrequent, expensive (especially if you have two passengers in the car), and parking at stations adds significantly to the cost. Of course, if the small WCML stations had remained open as local hubs, the train might have had a look in but these were arrogantly all closed in the late 1960s. So it's the car for us. But what about the horrendous cost and hassle of taking a car into Manchester? No problem, we use a free Metrolink car park and take the tram from the suburbs, but that's just for a few miles, 90% of the journey is still done by car.
Also with a car you can carry STUFF which gets very difficult by train. The vast majority of people who live outside cities NEED a car and will continue to do so, they do not have a choice. At some point they may well be unable to drive and may have to sell up and move into a town, unless they can rely on neighbours, demand everyone comes to them to visit or can use what remains of the local bus network. I do use the local bus which runs to the great frequency of once a week, but I have to alternate what I can do/carry in the space and time afforded by this, with an extra shop by car to buy heavy stuff or from business not in the town centre or when I have an appointment which isn't on a Tuesday - I try to be green, honest, but still need the car!
Oh, and very rarely I or my wife will use the train, simply for events where one of us needs to be away for a few days somewhere relatively accessible and the other needs the car in the meantime, on the proviso that the car-keeper does the long drive to the station both ways - we did have TWO cars but gave one up! But that hasn't been in the last two years.