Wow... That is brutal - and a million miles away from my own personal experience.
In the six years I've been at the University now (first as a PhD student then as a post-doc in Engineering) I've only known two people not to complete their PhD course, and that must be out of somewhere in the region of 50 - 100.
One was a guy who disappeared back to Singapore for four months without telling his supervisor or replying to emails. He didn't make it past his first year review.
The other was a Greek guy who was really not too bright (comparatively), but thought that everything he did was pure and undiluted genius. He got through to his viva, but failed. He was told that he could have an MPhil, but instead he decided to take the route of complaint letters and hour-long rage rants. Unsurprisingly this got him precisely nowhere, especially because his supervisor had warned him for months that he would fail unless he made massive changes (which he dismissed as "idiotic suggestions from a senile moron").
Anyway, I just can't relate to these statistics at all. A THIRD of engineering students haven't completed their course after ten years?! TEN YEARS?! At Nottingham there is a strict four-year hand in. If you don't hand in within four years (to the day) then you simply aren't allowed to submit. I know someone that managed to get a two week extension due to the amount of University-level sport he did, but an extra seven years?! Is this normal practice at other Universities?
I've seen plenty of students who were either incapable or unwilling to work at the level expected of PhD students, but (aside from the two I mentioned above) they all came through the process eventually - most of them carried by their supervisors, and all within the four year window.