They drive to remote places for cheap parking. Sometimes all night. The lines often depart from densely populated cities and bring that large capacity to the countryside. You may get thousands of seats for 2-3 customers. In the other direction it is the same. Last miles people are packed like sardines and bring in all of the revenue. If you have 500 seats a 3 euro ticket would at least pay for the trip. 50 cents is better than nothing. Shops at the train station bring in a large part of the money.

There is also a panopticon effect where people behave themselves decently if people are watching.