I in effect did. I showed up for what I thought would be my defense, and my chair wasn’t there. He had been replaced without my knowledge. Two other professors were there instead, neither of whom I thought were on my committee. One was extremely negative, compared my thesis draft to a New Yorker article and suggested that “You should look to your education.” Nobody bothered with any actual questions about the thesis. So to be precise, I didn’t fail the defense. It just never happened.
The other was more positive but thought much work was still necessary. After our meeting he wrote me a calm sensible letter outlining the required changes, and we met or talked on the phone several times subsequently. Over the next year and a half, while mostly working at a job in another city, I did the revisions. Key ones were working in a unreadable theorist I didn’t especially like and a verbal formula, not from the theorist, that I never understood and still don’t. But with these changes, which I was in no position to resist, the second professor found the redo acceptable and recruited a colleague who agreed.
Thus I had a real defense, which surprisingly was sort of fun. I got my degree and have remained forever grateful to the second professor. I did OK later but made a point of getting out of my PhD discipline so as to avoid running into versions of the first one. It has been a great satisfaction of my academic career to watch the striking long-term decline of the first one’s reputation. And I recently discovered that a high-level national politician you’ve heard of had hired him as a senior advisor. He lasted two days. I’d voted against the politician, but here he showed fine judgement.