Regarding item 5 (guests unwilling to pair up), what you say about it is true. However, solving the problem is not very easy at all. When I was in college, I was a ride operator at Disney World, and one of the rides I operated was Spaceship Earth, a continuously-loading dark ride where guests continuously load similar to a chairlift.
At a certain point, the operator needs to make a tradeoff between courtesy and efficiency, as enforcing a "no seat goes empty" in the rapid paced area of the loading zone can frequently end up with more seats going empty, despite efforts to the contrary.
Lift operators should certainly encourage full utilization of the lifts capacity when demand is more than a couple chairs worth. But beyond that, my experience is that enforcement is typically unproductive.