They might even make more profit if they didn't have outdated credit card rules restricting On-Line reservations. I know several Dutch residents living in Zuid Limburg who no longer fly BA because they want to fly from DUS or BRU but can't book on-line with a Dutch address & credit card unless they depart AMS! Consequently they use other carriers such as BMI and FlyBE who have no such restrictions.
For those of you who failed Geography O Level, DUS and BRU are an average of only 55 mins drive from ZL as opposed to 150-180 mins to AMS depending on the tfc.