Chicken and egg - why did they have such a poor service (one a day, or even one a week........) in the first place, even when, as in most cases, there is a train service passing through? In most cases, these "least used" stations are in sparsely populated areas, or there is a nearby station on another line with a better service. It costs money, in fuel and wear and tear, for a train to call at a station, and adds to the journey time for everyone else. If no-one is using the station anyway, why stop there?