Earlier quoted context omitted.
Do I understand your argument correctly? Effectively, what I'm reading is, "Because large tech companies do X, it's very important for everyone else too (including billion-dollar companies that don't do X)."
You're not understanding my argument correctly. I'm saying, in spite of it being cheaper to distribute their engineers and hire remote, they do not. These aren't companies run by incompetent people, and they're large enough to have some remote workforce, so they understand how remote workers compare to onsite with as few other variables changed. These companies hire onsite because it's important to be able to meet fa…
I'd contend that you're not considering the impact of sunk cost fallacies on business decision-making. Or if you have considered it, you've probably discounted it far more than is warranted.
It could be the case that, out of all the people currently employed by these companies, the majority believe they thrive in an onsite role rather than a remote one. Years of self-selection (especially if exacerbated by a lack of diversity in their employment experience, since these companies tend to hire out of colleges) could lead to a feedback loop.
Just because they're smart people doesn't mean they're impervious to human cognitive distortions.
How many of these companies have even trialed 100% remote positions, even if only for a year?