This kind of prep has been common place in other desirable fields for many years. Law, medicine, finance. They all have books, classes, etc. that you can take to prepare for interviewing, taking the bar, mcat, etc. Compared to college admissions, the CS interview process looks downright sane.
They all have prep for everything but interviewing. An interview to get a residency or a junior assistant position will be much more about your credentials and a history of your performance.
Finance at least has prep for interviewing for investment banking, trading, and consulting. When I was in undergrad it was common to have mock interviews and prep for commonly asked interview questions. Most people prepped on being able to walk you through basic financial statements, valuation, brain teasers, case interviews, and stuff like that.
I'll take your word for the other fields as I can't speak directly to interview vs exams there.
