I don't think this is true at all. Human social behavior is incredibly sensitive to perceived norms and paths of least resistance; this can be observed all the time in online games where minor changes to UI or reward structures have drastic ramifications on player social behavior. A lot of interaction simply will never come about if it isn't fostered organically by the environment.

This isn't to dispute that the benefits of an open office plan are fairly minuscule​ compared to the costs for most people, myself included.

Yes, but online games are a collective. Consider the case of open spaces where you have one team per aisle. Team 1 can be as noisy as they wish - there is no penalty most of the time from the unrelated Team 2. I was in such a predicament at a large e-commerce company - I was seated the aisle over from a very noisy team that ran in debug mode. They and their manager thought this was the way a good team works so my complaints were discarded with extreme prejudice. Two aisles over was a relatively quiet team with a very loud chewer/scraper - the person was very careful with his food and spent 5 minutes every work day scraping his plastic container right there at the desk.

I used to have to listen to white noise just to get away from the drip-drip torture of the endless prattle - my productivity at home used to be 5x compared to working in this open Hades.

I guess you are right - a lot of interaction will never come about if it isn't fostered organically by the environment. I am saying that in my case, what was fostered organically by the environment was people that first speak what they are about to type before typing it and utter every exclamation point associated with a failed `ls` or etc. It was Hades. I have ringing in my ears from listening to loud music and noise to drown out this aural rubbish and I can assure you that this ringing is a quintillion orders of magnitude more pleasant than the cacophony foisted on to me by the fine co-workers at this establishment, courtesy of the cage free office plan. I left as soon as I could and while I miss the money/benefits, I don't miss the noise - not one little bit.

I shudder. Your loud chewer story triggered a flash back to a coworker clipping their nails (talons) next to me.

About the noise pollution...

Like decision fatique, I think we all have a stimulation budget (buffer). Most of the time, I'm fine. Until I'm not. And my budget (buffer) gets smaller as I age.

Nowadays, I'm completely content to be facing a wall, with earbuds in, so I can tune out and get some real work done.

If I want to talk to someone I feel very comfortable going over to their office and having a conversation. At most I'm interrupting 1 person. In an open office or cubicle farm if I walk up to someone and strike up a conversation I'm interrupting 10 people.

This is very true. For starters, you will foster an entirely different level of relationship with a coworker 10 feet away from you than you will with one 30 feet away.

I've worked in several open plan companies, and what I find to be a key differentiator is that the companies that make it work: a) institute a reasonable minimum amount of space per person b) have enough quiet areas for people who find the open plan uncomfortable