Yes, this is true of just about any IT job, and I assume just about any other knowledge-based jobs.
I am pretty broadly knowledgeable and skilled for a member of my field. Nevertheless, I know less than 3% of my field (not including programming, which I consider totally separate) and only know about 2% or so of it very well.
For most people in my field, they know about 0.25% to 0.5% well — so even though I know a lot more than average, I still know very, very little.
I memorize a whole lot for certification exams, but 90% of the details are forgotten after six months.
Itโs odd that many IT hiring managers expect someone to know arcane details that they themselves often donโt even know, and if they do itโs only because theyโve been working on that specific thing very recently.
I know itโs adversarial and doesnโt help my chances, but during those sort of trivia question interviews I like to turn it around on them and start asking them about arcane technologies that theyโve not worked on recently.
Like I said, I know it doesnโt help my chances, but it sure is fun to smack down some arrogant doofus.