1. Company leases expensive office
2. Realizes that no one has to work from the office anymore so they're wasting money on this office
3. Inconveniences everyone by making everyone return to the office
4. Profit?
The lease is a sunk cost. They can try to sublease it out or pay some penalty to get out of it. Even if they owned it, why would they force people to come into the office and not just sell it? If it's worthless to them, then again what they paid for it is a sunk cost and they may as well just sell it. And why wouldn't they try to greatly expand their application pool to non-local workers if WFH is just as good. It's insane.
I've never heard a reasonable explanation as to why managers are so invested in commercial real estate prices that they'll collectively organize and forsake their interests to keep up the mirage.
The more reasonable explanation is that a lot of people work bullshit jobs or can skate by doing very little. These people are harder to control and less visibility by WFH makes it very obvious and managers don't feel good about it.