I may be a counter example, but I did very well at system design interviews at both Google and Meta (level L5), with no experience building such systems. As a matter of fact, my resume didn't mention any such things and everybody was aware I didn't have that experience - recruiters, interviewers. A lot of candidates don't have that background (there are lot of things to do in our field besides building Twitter newsfeed and Google search autocomplete), and companies don't want to exclude them.
Also, you can build knowledge during your preparation. It's not only about "faking" it.
Also, you can build knowledge during your preparation. It's not only about "faking" it.