I've worked in the US, Europe, and in Australia.
My experience in the US was that not actually a lot of work happened. The organisations I was around spent so much time on conference calls - there seemed to be at least 2 conference calls I was on a day, which are inefficient already, and you would have a dozen people on them where maybe only 3 people talked. It seemed the primary reason for this was because people just didn't read their e-mails. So you couldn't have a meeting of 3 decision makers and then feed that back to a dozen others, everyone had to be on the line for the call.
It was a lot of busy doing nothing. There was a lot of being in the office to be seen. It's 'Parkinson's Law'.
Yep. This describes every corporation I have worked for. The crazy thing is that they are always pushing for more production, but when I would suggest less meetings and more work time, the idea would shot down by the very same people working 70 hours a week. In the same week my manager threatened to cancel my vacation time because more work needed to get done, we spent almost an hour listening to some woman talk about her stuffed cat collection in a meeting.
The only way to survive was to work during meetings, even when my manager threatened to fire anyway caught working during the meeting(also threatened to fire anyone not getting enough work done... so...). It got to the point where a meeting with a large group of people was my most productive time of the day. No one was bothering me because they were all in the meeting.
In my organization there simply isn't enough time to do everything in the course of a normal week. Prioritization is mandated and is underwritten by leadership. There are still mandatory things that have to be done though. Because of this requirement, bringing your laptop to a 3 hour meeting and doing other work when it isn't your turn to talk is par for course. We also have a mandate that meetings will only happen on Mondays and Fridays. It means you could be in the conference room for several hours, but the middle of the week is yours to get real things done.
I needed to add more information to be presented during our Monday morning staff huddle, but I was told the meeting couldn't be any longer than it already was. This was a challenge to me and my staff to improve our speaking skills, but it also became a stealth requirement to the rest of the organization because it was a list of things they were late completing. The better they were at staying on top of their tasks, the shorter the Monday huddle. My boss hates long meetings, and his new boss hates them just as much. The previous boss' boss loved to hear himself speak. He'd show up 15 minutes late to a meeting, start off with a tangent for 15 minutes, allow the meeting to run 50% longer than scheduled from the new starting point, then blamed us for having to be lectured for so long. His replacement's first meeting started on time, lasted 60 minutes compared to the 90 it was scheduled for, then asked his staff to make it even shorter.
TL:DR: productivity and making best use of your time is entirely leadership driven.