I had a bit similar story, though it went a different way, and prompted a few other thoughts...
Earlier in my career (a few years before Google seemed to start the current techbro rituals), I went to an interview at a big-name CS dept. spinoff company which had the same problem: CS students and professors with no professional software engineering experience deciding what's most important for professional software engineers to know.
The interviewer and I were both senior engineers at well-regarded companies, but he gave me a coding exercise (this was not usual, at the time), and it was a CS101 tree traversal coding exercise in C. I'd happened to remember that day of class from community college, and I just did the exercise. Nothing to brag about.
Then he said "no one ever did it that fast before". So, feeling very confident and a bit disappointed/surprised, I started telling him what I thought was a better way to do interviews for software engineers. (Spoiler: it didn't involve regurgitating CS101 algorithms a person randomly happened to recall.)
I got the offer, and accepted the job, partly because we had a collegial discussion about the interview methods. Very smart and likeable people. But there were a lot of people who arrived from top university departments not knowing how to do software engineering nor even how to do non-homework computer programming, but they apparently passed the interview of the CS undergrads' idea of what's important to software engineering.
(Actually, the person from there who I noticed on LinkedIn many years later as eventually most accomplished from there, was the only one I knew came from a commuter state school, rather than from a big-name CS department. I don't know whether he would've gotten in, once techbro rituals took over. Maybe he would've, if his school's department had switched to teaching to the techbro interview; though, then, maybe that would've been at the cost of whatever skills development later helped him be so successful.)