Arrange own test, slower than through driving school

How come that if you arrange your own test, you need wait 4 months, while if go through driving school, it can be within a month. Seems very corrupt and discriminatory. The driving school charges about 5,000 sek for it including lessons.

Svenska: Vissa trafikskolor har behörighet från Trafikverket att kunna boka åt sina elever.

English: Some traffic schools have permission from the Swedish Transport Administration to be able to book for their students.

Priority is given to authorized driving school’s customers because they are much more successful than private learners in getting a pass on the test. Also, private tests are limited because Trafikverket has a limited amount of cars available.

Resources are finite. Driving schools provide their own cars and have a much higher pass rate.

Corrupt? Do you even know the meaning of that word?
Of course Trafikverket prioritize people who come from Driving school, since they... as a matter of fact has been cleared from the Driving school beforehand.