Such Interviews questions doesn't mean that you need to handle 100k RPS/s on the job
its just to test if candidate can think and apply certain software engineering design principles at hand. Understand approach how do they handle corner cases ( if they can identify) technical depth, also good way to test fundamentals.
For eg https://www.morling.dev/blog/one-billion-row-challenge/
https://github.com/gunnarmorling/1brc
Such problems really pushes candidates to thier limits. I love to go deep in OS & database, distributed systems.
Would love to see, discuss what interesting tough engineering problems you folks ask in interviews?