I work in an open floor plan. We have fairly standard carpet and ceiling acoustic tiles, the walls are drywall, so we haven't gone to extremes to soundproof but it's not tile and open warehouse ceilings either. We have a culture of being reasonably respectful, but will still have conversations at times. In practice... I find myself hardly remembering the people that exist even 20 feet from me. In theory I can see about 50 people, but I almost never actually remember that. I'm somewhat sensitive to conversation and
extremely sensitive to music (can not
stand music I'm not in control of), and I'm fine.
I do have modestly nice passively acoustically isolated headphones and frequently use them, but I do that anyhow, not because I'm trying to dodge noise, and I can go hours without them just fine, usually putting them on because I want music, not isolation.
I find myself wondering what percentage of open office complaints come from A: people who are simply psychologically unsuited to them under any circumstances B: people whose open office experiences involved tile floors, warehouse ceilings, and glass walls, which would be a completely different acoustic experience and C: people who haven't actually spent any time in a decent one and are just assuming they'd hate it. No sarcasm. For that matter the studies that keep asserting how bad they I find myself wondering about A and B... certainly you can construct an open space that does suck, but that doesn't mean they all do, and I've never dug into one enough to see what they specify as the "open space".
And to be clear, I'm not asserting that they're obviously better and everybody should love them (and let me reiterate I completely believe in the existence of a set of people who will never like them), but my experience just doesn't seem to bear out the "they suck and can never work and why on Earth would any company ever put them in" attitude... at most it seems like they might be slightly worse on average but it may be below the noise threshold, and it would be the incredibly-perfectly well-run company for whom this would be their biggest problem.