That first impression (and how you tackled it) of system design interviews makes me question their usefulness. Like, how good of a signal can companies really be getting if it's too different from real world systems? Feels like an artificial wall too - many companies don't approach the scale where this stuff matters, so getting that experience is hard.
> Like, how good of a signal can companies really be getting if it's too different from real world systems? There are "layers" to the signal you can get from system design interviews: 1. Are they aware of "big concepts", indexing, sharding, queues, scheduling, etc. 2. Are they comfortable actually using and manipulating these abstractions in an academic sense? e.g. new college grads may have never used an index, but…
I think pulling specific ideas from your actual system is full of traps. These are probably problems you've thought of - both actively and passively - for days, months, or even years.
The person you're interviewing has had no such benefit, and it might be very hard for the interviewer to be able to separate what they think is reasonable and what is actually reasonable.