If a mock interview averages 30 minutes from start to end, including the time to get on the call and take notes and give feedback, that's 30,000 hours of mock interviewing. Working 8 hours a day that's 3750 workdays, and with 261 working days a year that means you've done mock interviews full time for more than 14 years? Are the interviews super short? I feel like I'm missing something here.
She's the founder of interviewing.io, which is a mock interviewing platform. So I'm guessing her insight comes from looking at all the metrics (e.g. pass rate, strengths/weaknesses of candidates) from the mock interviews hosted on the platform.
That being said, I'm sure she has conducted her fair share of interviews.