Earlier quoted context omitted.
Volume. Huge volume. Google has a completely broken interview process, to the point where they pretty much brag about how ridiculous their false negative rate is, but they make up for it on volume. When people will throw themselves at you two or three times in hope of getting that lucky set of algorithm wankery questions that they can answer, then you will keep interviewing like that.
How do you define broken? It definitely sounds like it's working for Google so going by the "is the process working for the employer" definition it isn't broken.
If true, hiring based on luck seems broken to me. Like the joke of the hiring manager throwing away half the resumes and not hiring "unlucky" people.