Driving Tests in Ireland

I was listening to NewsTalk 106 on the internet yesterday and heard all about the meeting yesterday that meant that 1300 driving tests had to be postponed while a decision was made on the option of bringing in a private company to help the problem of the 40,000 people on a driving test.
I've had a look at the info on the Department of Transport website to see what the figures were like. The shortest wait is 23 weeks in Clifden and the longest is 60 weeks in Raheney. The average wait works out at 43.3 weeks. That's nearly 11 months! Jesus that's mental.
But I've got a question...the average pass rate is 53.6%, so why is it that someone that has 11 months on a provisional licence to practice driving that they still manage to fail the test?
Anyway, they have decided to get the private company in until they reduce the waiting list down to 6 weeks.