Also. Open plan doesn't mean you put sales next to coders.
This reminds of my first job out of college (mid 80s). I worked chip design for over 30 years and started at an aerospace firm. They used cubicles, but depending up on your seniority/importance could be in a cubicle/bullpen with 3 other people, 1 other person, a "private" cube, or an office with a door. Anyway, being fresh out of college I was in the 4 person cube, just over the wall from the the purchasing folks. It was just awful, as they were talking and on the phone all day long. To make matters worse, it was in the day and age when you could smoke at work, which they all did and it just came over the top of cubicle wall like a water fall. It was simply awful. Fortunately, my job at the time required a fair amount of lab work, so I had an escape during much of the day.
My next job, was at a university (late 80s-90s) and was the only job where I had an office with door that I didn't have to share with someone else. We a suite situation, which was really nice. Several offices off of a common space. This was really the best of all worlds, as you could close your door and have focus time (or change into your softball clothes at the end of the day), or you could all collaborate in the common space.
Later, at a well known high tech company (early 90s-mid 00s), it was the classic one person cubicles. Meh... no doors, so you could be interrupted whenever someone wanted to, and you could hear conversations from all of the adjoining cubes. Yes, it allowed for "over the wall" collaboration, but was often noisy and distracting. Throughout my career, my job required concentration to design and/or debug things. In this environment, I never felt I was able to perform as efficiently as possible.
The last job at another well known high tech company(mid 00s-now), was similar to the previous; however, they liked to include open collaboration areas. They started as converted conference rooms and finally resulted in open cube space allowing 6 to 12 folks to work in one open area. There were times when this could be useful as collaboration was needed to push to a design milestone, but often they were overused or included people that weren't working on the core area requiring collaboration. They also make concentration nearly impossible, as there are always several conversations going on, which often don't pertain to what you are currently doing, but you need to keep an ear tuned just incase. Yuk! So in small doses they could be useful, but they were abused. There is a reason why these were called "dungeons" throughout this company.
From my 30+ years, I definitely like the university suite arrangement the best. I found it balanced the need for collaboration with the need for privacy and focus time the best. The multi-person cubicles were awful, and were very unproductive. The solo cubicles, unfortunately, are the industry norm and an attempt at some privacy with openness. In reality, what they are is a low-cost attempt at providing a little personal space. They are much better than the open collaboration areas, but not much. The open collaboration areas can be useful for small groups of people for short durations of time, but only when close and constant interaction is required.
I haven't even touched on the ability personalize your workspace, which is hugely diminished in an open office plan. Allowing people make their space reflect their personality can go a long way to giving those workers better warm fuzzies about things. This really does matter in happiness and job satisfaction, which in the end provides better efficiency and job loyalty.
The bottom line is that the employers have probably considered all of these issues and weighed them against cost. It's all about cost and profits. If they believe it is more profitable to choose one over the other, that's the way they will go. It doesn't matter at all what the employees want, as long as they are paid enough to keep them from walking out the door.
Thanks for your time. I've wanted to make this comment for years and saw the opportunity.