Some groups have this down to a science for their particular industry (say, Apple supply chain logistics) and others aren't even aware of the issue and pass it off as expected.
It would be an interesting study to get queuing theory people, lean experts, or some such qualified group to look into public construction and maintenance projects to simulate and analyze optimal vs. actual. No question this would be very hard to do because unions hate this kind of thing and people don't like being measured over their shoulders and the basic implication that they're "lazy" or inefficient or whatever. (it's hard to measure and improve worker output while actually making the worker happier too because there tends to be a Stanford Prison Experiment vibe where you get managers nitpicking lunch breaks and the basic pleasantries of working instead of bulk errors like allocating skill sets)
It could be fairly straightforward to compare the efficiency of the same task in both countries.
You say that as though the policies and procedures by which worn is done haven't intentionally been made inefficient to create work for the workers.
I once sat on a train for 3hr waiting for a railroad employee to show up with a chainsaw and cut a downed tree of the track. There was another employee in a service truck equipped for brush clearing a couple miles away at the station waiting for his wife who was stuck on the same train. He couldn't clock in and deal with the downed tree, because rules. This story is fairly well known among people who ride that rail line so some here may recognize it.
This looks bad, and some of the time it is just inefficiency, but in many cases there may be a series of tasks, dependent on each other, some of which require a lot of laborers and some that don't.
It's often better to employ a welder for the day than to stop work entirely when you don't have one milling around on site waiting for their next task.