I don't buy this narrative. While it may very well be true that real estate is going down and ruining some companies and people, which makes me very happy, I doubt this is the reason why companies are pushing people to office.
IMO they're simply dumb controle freaks. When people are at the office, they can push their propaganda of corporate culture in the hope that some workers will buy it a become some kind of ambassador for their twisted model.
There probably is also the same stupid generalisation that made open space a generality: some idiot with way too much power prefered to work this way, and thus he assumed everyone would. It was turned into company policy, and because this company earned some money this year it turned into a fashion for all companies.
I didn't think about the "ambassador" angle. It probably is harder to get employees to drink the company koolaid when they're not physically in the office.