Hiring.. too many or just enough interviews

Many companies in the high tech world are known for their arduous, protracted, laborious and unpleasant hiring practices.  Google, Microsoft and Apple can have a prospective employee interview as many as twenty potential peers. 

Is that too many?     

I think it is too many because it doesn't work in the short run or the long run.

In the short run the goal is to screen out potentially disruptive, lazy, disingenuous, malingering and technically unqualified applicants. Twenty interviews doesn't work.

The effective way to do this is to have a series of long interviews with top prospects.  A breakfast interview, a lunch interview and a dinner interview.  4-6 hours with one or two qualified interviewers can do all the complex and subtle screening much more effectively than a group.  Some snooping around among friends at the prospects previous employers is sometimes possible and obviously effective.

In the short run, many good applicants won't tolerate this endless interviewing waste of their time. Often really good applicants will have taken another job before the end of the interview process and the interminable waiting.  Meaning the long interviewing process only weeds out top tier employees.

In the short run the goal that is achieved is to select applicants who will comfortably fit into the group they will be working with.  In my opinion this is shear stupidity.  A good team, in business, always has a wide perspective that comes from ethnic, personality and intellectual diversity.  Careful screening makes a good team of robots but nothing else.

Fortunately, because employees move about the company over time, this initial screening stupidity gets mitigated by all the differences within the company.