I think one of the main issues sort of stems from it being called a driving "test" It makes people think of them as similar to GCSE/A Levels when they are vastly different things
We have this preconceived notion that failing a test means that you are not capable and passing a test means you are. I bet we all know at least someone who has passed and isn't that great on the road. I could almost argue that being called a newly "qualified" driver is a bit erroneous, Its not a qualification and you are still and will forever be learning
As for your test, I wouldn't say it would be anyone's fault but your own, don't take it the wrong way but you made a serious error when driving. Keep going and practicing with your current instructor and you'll get there. The new test isn't vastly different than the old one and if you are at the stage you can take the current one, you're more than prepared for the new one. I know failing your test is a bit of a kick in the teeth, especially if you had a decent drive but consider it this way. Would you rather make a mistake in a semi controlled setting, i.e with your instructor or examiner where they can intervene or pass first time, and make the same mistake but with no one there to help you. I failed one of my tests for mirrors because I almost blindsided a lorry going around a car turning right. I was gutted but if I hadn't been on test, I would have blindsided that lorry, wrote off my car and possibly ended up in hospital. Because of that mistake, it is now ingrained in me to check my left mirror
Your mistakes make you a better driver in the long run