Technology

If you have an unutilized asset, there's pressure to get rid of it for the cost savings.
If you sell your asset at a loss, it looks bad for you and the company. Same for paying cancelation fees.

If you legitimately think that you're going to need that space in the future, for example because you think that we'll find an equilibrium between "everyone work from office" and where we are now, and that we're trending towards an organic level of office need/desire higher than we're at now, you might see selling now as the first step to needing to buy again later, likely for higher than you sold for. So you try to "mandate" the equilibrium that you expect so you're not in a position to have to explain why you're holding onto a dead and losing value property.

Executives spend a lot of time talking to people and having meetings. The job selects for people who thrive on and value face to face communication. Naturally, they overestimate how much that social aspect of the job is true for everyone else, so they estimate that the equilibrium will have a lot more office time than other people would.
To make it worse, the more power you have to influence that decision, the more likely you are to have a similar bias.

This isn't an excuse of course, since you can overcome that bias simply by telling teams to discuss what their ideal working arrangement would be, and then running a survey. Now you have data, and you can use it to try to scale offices to what you actually want.