Well, it's not only big SV corporates that are doing 5-7 rounds of interviews. In my experience even 3-4 year old startups with under 100 employees do at least

Well, it's not only big SV corporates that are doing 5-7 rounds of interviews. In my experience even 3-4 year old startups with under 100 employees do at least 5 rounds - 2 coding, 2 system design and one hiring manager. The most common 6th round is either "culture fit" or "bar-raiser" but small startups usually don't do this.