I understand that some people in certain roles would do much better with no interruptions in a private office but it's not a one size fits all solution. If your work consists of something you can mostly do on your own that's certainly one case where private offices might be a win. If your work consists of lots of collaboration it seems less clear. At least to me.
I'll also note that at least for me I'm much happier around other people than isolated in a private office. I'm not saying I want to be an a 1960 bullpen but a room/area with 2 or 3 other coworkers I'm working on stuff with is my personal ideal.
A private office doesn't mean you have to work on your own, it just means you have the option to.
So, IFF your company has the money to devote a fair amount of real estate to each worker, yes, private offices are great.
Even with just 4 of us, it means there is a good chance someone will be asked something, and regularly the head comes down to discuss stuff with one of us (often me). I can deal with it for the standard bug fix type work, but trying to learn something new is really difficult with constant interruption.
Folks younger than a certain age miss out knowing the social etiquette relating to visitors chairs, such as stacking "stuff" or coats on your visitor chair is anti-social and very strongly frowned upon. Also it was socially acceptable, standard even, to simply walk into someone's cube and sit down in their (visitor) chair and wait till they could talk, especially if you were (currently) working together on something.
Also "back in the old days" we had intentionally unreservable conference rooms scattered about. So if you needed 6 people on the spur of the moment you simply walked in to the nearest empty room, confident no one reserved it because it was un reservable.
This is pretty much how things were in the early 90s or so. Honestly I don't think I could handle the constant interruption and infinite distraction of an open office, which makes me think about a startup or something; I just can't imagine working in a "modern" office environment. It just sounds horrifying to productivity, like a prison yard or a doctor waiting room or something. Creeeepy.
As a parent when I need to get stuff done at home, like if I'm working at home, I kick everyone out of the room and work in peace and quiet. I never, ever, invite seven neighbor kids over and hand out toy whistles as a gift and nerf toys and then sit in the center of the maelstrom and try to concentrate. Nobody who "works at home" sneaks into a day care center with their laptop to concentrate on their finest work. There's a time and place for that kind of stuff, and its not the workplace.
That said in addition to a mandatory visitors chair, white boards everywhere. Just fucking everywhere. Nothing seemed to help collaboration like being able to start water cooler level talk about a problem and with out even noticing transition to hashing it out on a whiteboard.
So the "old timers" get very strange questions like "what if you're in an office and need to talk to someone" where the younger people don't understand the architecture and the older people don't understand the younger people's lack of experience.
In 1995 the office I worked in had 4 desks (usually 3 empty because of flex time/remote work, meetings, collaboration, etc) and 4 chairs (again, usually 3 empty) and two big lunchroom sized folding tables and I believe six chairs crowded around the lunchroom tables. Admittedly mostly covered with these new fangled (at that time) "cisco multiprotocol router" things. So if someone walked into my office and wanted to talk, or even a moderately large team appeared at my door with pitchforks or whatever, I could and did occasionally host parties of ten plus people, like if there was an emergency and we had to config and ship out like an entire data center of routers at the same time. And yet most of the time my office was ALSO blissfully empty and silent so I could concentrate on studying release notes and design new configurations and test network designs using routers set up all over the conference tables. It was extremely flexible, and therefore extremely productive, unlike an open office.
People who don't have experience with offices have these bizarre notions about office etiquette and collaboration. They also easily fall into post hoc / confirmation bias fallacies, where they see some positive result of collaborating in an open plan office and imagine that they would be forced to live in a world without the benefit of that spontaneous collaboration in an environment with offices. But they ignore the fact that such things very much do occur with offices, and they also ignore the opportunity cost of open plan layouts. Of conversations which don't happen because the work space is deathly quiet due to everyone trying to work, and you can't just hop into a friend's office space and close the door so you don't bother other people, as just one of many examples.
90s office work reminded me a lot of dorm room life and culture. Dorm culture probably hasn't changed in the past couple decades, and having dorm rooms with doors hardly eliminates all social activity; if anything it encourages it and military basic training style barracks are not considered a requirement of socialization.
PS: Loved the dorm room/barracks analogy
"Oh, some guys from floor support were doing that, something about the new cubicles."
"WHAT!! Where the hell am I going to put my books! This isn't enough space, blah blah blah". He was a hot head and immediately flew off the handle, much to our pleasure. Well, a year or two later, we did actually go to smaller cubes, and then a few more years later to the "open" floor plan (un-ergonomic tables with no kind of adjustments). People way to close to each other. While it does come in handy when we are discussing problems and bringing new people up to speed, I definitely think the negatives outweigh the positives. Sometimes I just don't want to be around people!
A few people working together on a single task is not an open office. In a "real" open office you couldn't actually talk to the artist and designer beyond a few sentences because if you did you would disturb the other 10-20 people within earshot.
10-20? There are about 80 here.
As others have mentioned this is where the definition of open breaks down. Team environments are great. Many open office advocates are small companies who, because of their size, are really advocating team environments.
Now grow that same company to 100s of people and see if the open office still works. What I have seen is that even the biggest open office advocates start putting up walls (even if movable) and segmenting once again into a teams.
TLDR; Team != Open
However, on-the-desk quants and IT are genuinely respected for their sacrifice. Sure, they have to be highly available from 9:20 to 4:10, but the rest of the time is completely their own (usually for research; they tend to work 11-hour days not because anyone is making them, but because they love the work). They're paid very well for that intense 7 hours, and no one would subject them to the humiliation of "Agile" micromanagement. Quants have traders come by to ask about trading strategies at high levels, but they don't deal with PMs and "story points" and arguments about whether what they worked on over the past week was "in the backlog" or not. Quants have something much closer to an open allocation environment than most software engineers, and if they can't hack the stress (and not everyone can, especially for years on end) of being on the desk, they're usually moved to off-the-desk roles and the change isn't stigmatized.
(Some will come in and say that quants are second-class citizens in hedge funds and, if one looks at 95th-percentile compensation, that appears to be true. Quants hit a ceiling around $500k-1.5M, which is 1% of what the best traders make, but they're respected. On the other hand, non-managing programmers are third-class citizens in most Valley startups, and they aren't making any money either.)
Open-plan offices make sense on trading desks, just as "Agile" makes sense for a small consulting firm on the make-or-break project that'll take it into the big leagues (under which it's reasonable to ask the tech staff to truly "sprint", because delivering the project will result in a quantum leap in client relations, quality of work, and compensation). The problem is that management tends to take these processes that conditionally result in high performance (for a short while) and attempt to implement the costly, negative and painful aspects (e.g. open-plan offices and Scrum) while failing to deliver the upside (e.g. quant-level bonuses, genuine equity rather than 0.05% bullshit) that makes talented people willing to tolerate the pain.