On second glance, though, employees also face a national market rather than a local one, and can be underbid for the job by anyone in the country. Maybe employers like that, and employees don't.
But maybe it's like this: WFH means that employees can leave more easily. If you work in the office, and you're in my town, there's only so many places you can go. I can mistreat you (bad bosses, bad raises, bad working conditions), and your options are somewhat limited, and you're more likely to stay. But if you're full remote, the whole country is open to you (without even a relocation), so you're more likely to not take it.
So I suspect that maybe bad bosses and bad companies want to avoid WFH, because remote employees are less constrained to put up with the bad conditions.
It seems funny to me how people always look for the ulterior motives and give basically no chance to the explanation CEOs give (collocation leads to a more productive organization).
Because it's horseshit, and everyone knows it. The only orgs that truly need colocation are those built around non-digital machines. Anything data based can be handled through one screen as well as another.
More likely to me is that many managers were coasting and not needing to actually track work, manage, etc. there’s a big pushback when they’re forced to actually do their job and not just rely on butts in seats.
Well no, there have been years of chances for those CEOs demonstrate their position. That's precisely why no one believes them anymore.
The problem for them is that there has been zero evidence for what they're saying. No one has been able to actually demonstrate these supposed benefits (or, more precisely, the supposed harms to productivity that WFH brings). You can see this in how their claims shifted over time: in the early days of the pandemic WFH shift they offered the productivity claims you note, but it soon became clear that there wasn't any evidence for that. Then the claims shifted to vaguer, non-measurable ones about office culture and exchanges of ideas. When that didn't really convince anyone it finally shifted to "you have to because we said so".
So you're getting it precisely backwards: it's the proponents of returning to the office that now offer theories of conspiracies and secret data that totally support these moves but somehow can't be shown to anyone.
That's not exactly true per se. My wife is from the country of Tunisia and my plan was to live and work from there, but once I got to the offer stage at each and every company said I must work within the US citing IRS regulations. While I'm not entirely clear why I've also seen a number of remote jobs that are only eligible in certain states within the US as well.