If you'd have told me that Okta has 540 employees, I would believe you. Even double that seems plausible. But damn, 5400 is a lot.
The reality is that while there obviously was overhiring, (the generic) you do not have a true understanding of the totality of Okta's (or any of the other companies') businesses. You know what is public/user facing. That is it. Companies scale/sprawl because running a large publicly traded company is actually very complex.
Hell, run a startup and you'll understand the complexity. It's not just ship code, get paid. Shipping is often the simplest/most straight forward part.
I do get how/why headcount needs to balloon; thankfully I've mostly worked at places where we kept things lean and mean. For me, things stop being fun once head count gets into the hundreds!
I don't tend to think about the scale of companies in terms of number of employees. I'm often very surprised at how big or small a company is, especially based on their perceived size.
I also think this is a good forum to have those discussions on. Many people here either work in tech, have worked in tech before, and maybe have solved similar problems at similar scales to other companies before.
It's only natural to look at a company that seems to employ 10x more people than you expect and wonder "what the heck are all those people doing"
I think P's frustration is that saying "Wow, $Companys head count is high" on every thread is not an interesting, insightful, or discussion driving comment.
Why is the headcount high (outside the obvious)? How could it be prevented in the future? What are the ramifications of this in the future? Even as you suggest, why not respond to "What the heck are all these people doing?"
Not "Wow, headcount high!"