He hired thousands, even at the top he hired hundreds, he relied upon others. Put yourself in that position, and. have you ever misjudged somebody? Happens all the time, you hire someone who interviews great, but can't do the job.
I use to be in the interview chain at my former company (retired). I would look over the resume and have a casual talk with the applicant. Many times I would give a thumbs down on a candidate however my boss hired them anyway. All of them were gone within a year or two. I was there 28. Go figure.