Let's assume the average gondola will house 5 passengers and they depart the station every 10 seconds. The system would move about 1800 guests per hour in a single direction (5 passengers x 6 cabins per minute x 60 minutes).
If we compare a peak bus guest load of 50 passengers including standing room, that's the equivalent of about 36 full bus loads per hour.
The killer route on this thing from Disney's perspective would be the CBR to IG spur. Right now, most Disney buses are only maximized in one direction. In the morning, a bus going from CBR to Epcot is full on the way in but then departs Epcot virtually empty. At night, it leave Epcot full but picks up few passengers at CBR. But that gondola route will be simultaneously used in BOTH directions all day long; guests going from Epcot resorts to Hollywood studios and back, while guests from Pop/AOA/CBR go to Epcot and back. Using my numbers above, in a single hour that spur will move 3600 guests or 72+ bus loads. (Though admittedly there could be bottlenecks if a car switch is required for some trips.)
During peak periods, Cast Members could group multiple parties together, coming closer to the 8-10 maximum capacity for every gondola. And I suspect bus or boat service will still be offered between these resorts & parks, albeit with reduced frequency. They simply cannot mandate that every guest ride in these windowed cabins 50' off the ground.
I'm curious to see if guests will actually have to change cars at CBR or if they'll use some computerized switching system to have cars just pass thru that station if headed to or from Hollywood Studios.