At my current job, I did about the same number of interviews. Not counting an initial 15 minute screening call, I had a 30 minute phone call with two of the engineers on the team, a technical panel interview, and 3 exec interviews. So that's six interviews. I would be working with all of these people directly and I wanted to avoid "broken stair" coworkers I have had in the past. While I found this valuable, I didn't feel the same way about the Canonical process and refused to proceed. Each stage of an interview process needs to provide value to both sides. As a candidate, a personality test or an essay does not help me at all except to raise a red flag. And speaking to many people who I might never speak to again is useless to me.
If you interviewed 3 executives, I’m assuming your senior leadership yourself. Or, at an actual start-up where the execs are still doing IC tasks. I can see the need for a higher bar in either case.
But for an average developer at an average company? That just sounds insane to me.
