I've never seen anyone say they did open plan because it was cheap, they just say "improved collaboration, more open space environment" etc. Of course the main motivation is likely to reduce cost, but I haven't seen people say that explicitly.
So I think that the propaganda in favor for open space offices really sped up their adoption. If Google now produces a lot of propaganda in favor of this hybrid wfh model then it will likely also help speed up adoption, although the main reason to do it would be to save office space costs and not the propaganda blurbs we will see.
Corporate environment is rarely honest even if everybody knows what given thing means. You can literally compose dictionary to normal speech at some point.
I have a theory this environment slowly corrupts a character in subtle ways, till folks wake up one day being full of shit while being polite and smiling and when asked everything is fine.
So I think that the propaganda in favor for open space offices really sped up their adoption. If Google now produces a lot of propaganda in favor of this hybrid wfh model then it will likely also help speed up adoption, although the main reason to do it would be to save office space costs and not the propaganda blurbs we will see.