If you're hiring for a specific skill set it might be because you have a target you're trying to hit. In my experience purse strings typically open because the company has a new project they want to complete in N time, and need X additional headcount to accomplish the goal in the time required. If it takes 3-6 months to onboard someone, you might not get your new headcount fully onboarded before v1 of the project ships.

It doesn’t take 3 months to do this even at wholly internal faang environments except in some special cases.

Most of what people are talking about can be learned in days because they’re 90% the same as other products. Sometimes it's hours as someone else said because they're just generic databases or a pubsub system.

And then you get an edge case bug with the new platform and the new guy takes N times longer to find the root cause because it's his first time using the platform.

Or the design is wonky because the new platform isn't a 1:1 match to the proprietary solution.

100% agreed that it's dumb to require extremely specific knowledge of one product, and 100% disagree that a Googler is "clearly qualified" simply because they came from Google. I have absolutely no idea why we've all just accepted the narrative that any FAANG employee is automatically better than the rest of us, despite evidence that FAANGs are nothing more than code mills optimizing for exploitable ambition over actual intelligence or engineering ability.