[willjp]

I think one issue is that meetings aren't deliverable. Their benefit is abstract, it does not directly affect the business goals, or the bottom line.

I think another issue is that task switching can be very difficult. If your work day is split up into 1-1.5hr chunks of work, for some of us (myself at least), it is difficult to get enough momentum to steamroll through a task. I find it much easier to work after everyone has left, the pressure decreases and I find myself calm, and with regained control of my wits.