Do you live in the Netherlands? Because if you would, you find out that yes, there are many trains per day between the important cities. Not very efficient if you happen to live outside the main lines. The number or tracks are limited and accidents are frequent in the winter. So trains get delayed or cancelled. Not fun when you really can't miss getting to the destination on time - say from Den Haag to Schiphol.
Its all fun and games when things work out, but they don't all the time. And not to mention its really really hard to return from shopping at Ikea by train.
Biking, sure, fun, but not so autumn/winter/spring, especially in the areas close to the North Sea. The humidity and the wind makes the cold not very tolerable.
I could go one for a while.