Google had looked at some internal data and decided that after four interviews, you don't really get any increase in signal: https://rework.withgoogle.com/blog/google-rule-of-four/
The article you linked ins from 2017.
I interviewed for an are position in 2019, and I still had to go through 7 interviews: hr screening with dumb trivia questions, phone screen with coding questions and then five (!!!) more interviews in a single day on-site.
(For the record, I didn’t pass something on the in-site interviews, in my opinion nothing I couldn’t have learned)
It's possible that this wasn't really followed in the hiring process - doesn't mean that the conclusion isn't true. I guess it seems counterintuitive on some level that more interviews wouldn't yield more signal.