It's not just price.

Think about how trends evolve over time and how long it takes larger companies to "catch up". The planning/facilities groups are still high-fiveing from the major work it took to spin up open layouts, ignoring the growing evidence that it was the wrong direction.

And completely opening and shoving people in like cattle is way easier than "well-planned open" (as mentioned in other comments), or even closed offices.

They're not about to embark on an expensive complicated project until it's unavoidable.

Will be years if ever.