Are we disagreeing here? I'm not sure how you took my comment, but it seems like what you're arguing here doesn't really rebut what I was saying. Or at least is not directly related. FWIW I agree with everything you're saying, except for the tone, which, to be honest, I don't love.
>" Maybe the answer actually was they didn't/don't.
I'm disputing the claim that the above statement was ever in question. FAANG doesn't employ people because they mistakenly thought they needed that many, they do it because adding more employees has either lowered their infra costs or increased their revenue.
Typically cutting is a top-down decision, while hiring is organic. If they think they can justify budget for it, managers want to hire. Managing more people has direct rewards apart from anything the headcount is doing for the organization overall, so incentives are misaligned.
All the big FAANG companies that did major layoffs have rehired to the original amount since then.
I really believe the layoffs were not about needing less people, it was about gaining some ground in the employee/employer dynamic.
From a pure economics perspective, this is healthy for the business.
There are always low performers. Periodically transitioning out the bottom 10% or so, and rehiring different people, possibly in a different departmental distribution, is always net beneficial to the company.
Using regional/national/global events as the explanation is always better than blaming yourself.
Of course, it's impossible to segregate people into performance bins with perfect accuracy, and it's always bad for individual humans in the short term.
Arguments are made that it's good for society in the longer term, and wars are fought between opposing sides of that opinion. :)