If there already is rail infrastructure, it is unlikely that you are improving anything by demolishing it and replacing it with a bus. Whether it would make sense to build all those railway lines nowadays is a different question, but demolishing them where they already existed was in no way an improvement. Buses never have any real advantage over taking one's own car on the same route. Trains can have an advantage because they are more comfortable and can bypass traffic jams.
The map would look quite similar in many other European countries too. The widespread adoption of cars killed the demand for many of those railway lines. :(