I don't disagree, but I'll also point out that it isn't much better with cubicles. When I worked in a giant company that had cubicles in the 2000s, it was the same: a significant part (not half though) of the floor space was dedicated to meeting rooms, because you can't have meetings in a cubicle easily, and for privacy, serious discussion, etc., you really need a meeting room. So a company like that, which is already set up with the 1990s standard of cubicles and meeting rooms, could easily see an open-office plan as a way to save money and pack even more people into the office buildings they already have. All they have to do is take out the cubicles and stick a bunch of tables in, and leave the meeting rooms as-is.

But yes, if they had proper offices, they wouldn't need many of those meeting rooms, only some larger ones for meetings that are too big for the offices (more than 3-4 people perhaps).