I think it is people who control purse strings. One big problem is that majority of today's management is indulged in a bad faith argument of collaboration and innovation as benefit of open office. Management can own up and say its gonna save them money and it will continue with open office policy.

At that point employees may not like it but it would make clear that they need to put money where their mouth is and demand a separate cube etc at work as part of job offer. Not getting it would be like so many other compromises that we make in life and has to be endured.