Open plan offices aren't going away and nothing will really change because open plan offices have long been used where lots of people spend all day talking on the phone.
Acoustic privacy is has two components. Attenuation is the obvious one. Masking is the one that's not. Controlling rather than minimizing white noise from air-conditioning is the ordinary approach by professionals.
Of course, a lot of open office designs are driven by "taste" rather than judgement informed by experience and science. So you get hard floors and hard ceilings instead of carpet and acoustic tile (it's right in the name, duh) and complaints.
In other words, it's a solved problem. Poor choices aren't.