larger people movers have an efficiency advantage, like extreme carpooling. So I think there is room for improvement over the individual mover. As well as movers like trains are steel wheels on steel rails, and have a low frontal area for their length, and they don't even have to carry their own batteries (and can regen back into the network).
The most "efficient" system manages and predicts what sized people movers should be where and when, so the people don't have to wait *too* long between movers, but also so the movers stay reasonably utilized/loaded.
And there is probably another level of efficiency beyond that, but I cant think of it right now
