Two Kinds of Schedule
Most powerful people run on the manager's schedule: the day is cut into one-hour blocks, and you can change what you're doing every hour. Booking a meeting is trivial. Find an open slot, done.
Makers (programmers, writers, anyone who builds things) run on a different clock. They need time in units of half a day at minimum, because you can't write or program well in units of an hour. An hour is barely enough to get started.
Neither schedule is wrong. The trouble starts when the two collide, because the manager's schedule is the default among people with power, and they impose it on everyone else without realizing there's another kind.
Key idea
Managers work in one-hour blocks and switch tasks freely. Makers need half-day blocks because real building barely starts within an hour.