I take issue with this. For most of my career I worked in a standard office building. False ceiling tiles, cubicles, rectangular concrete 'tilt and pour'. It served the job well. It was relatively quiet, comfortable, intimate and fostered my productivity.
Now I work in an architectural masterpiece of modern green engineering. It is loud, impersonal, distracting, and not at all conducive to actually getting work done. It's like the people who designed the building hated engineers and typical engineering personalities and set out to design a building to torture them.
Apple has a similar problem. Apple's senior vice-president of hardware technologies Johny Srouji refused to move his team into their new, piece of shit exercise in architectural masturbation.
Plus, personnel costs (especially in Silicon Valley) are a multiple of floor space, so I can't understand that argument either.
But then, so far, I've never had someone who calls the shots on the open office model go public on why they went for it. I mean the cynic in me thinks it's about cutting costs (but then why do they have developers in SV instead of outsourcing it?) or showing off (open offices look good on pictures / when the manager walks around in it).
It's obvious to identify the product of Silicon Valley companies because they generally are marketed globally. But it's really hard to convey what it's like to live and work here. Generally, it's nothing like you might imagine. The architecture is mundane, the weather is great, the traffic stifling. That can describe many places, so then you have to talk about housing costing more than anywhere in the world (at this scale), and $12,000 bottles of Cognac at Costco.
In the end, it's the people who live here. Generally well paid, disproportionately wealthy (but not nearly everyone), probably from another country, not here to show off what they have, but rather, what they can achieve.
[0] https://www.youtube.com/watch?v=YQy0ZCx3UCY