[joncrocks]

I'd be interested to know if this was true.

People walking have to keep some space between them, and people also walk/climb stairs at different rates. You can only climb the escalator as fast as the person in front of you, and them the person in front of them. It only takes one slow-poke to hold everyone up.

So people not walking might in fact, on average, increase the throughput vs. all-walking.