A Siemens S70 LRV such as the ones used on the LYNX Blue Line in Charlotte, NC, can hold 68 passengers sitting, 230 including standers. One train comes every ten minutes peak, fifteen minutes off. This means we have a max capacity of 1380 pphpd (passengers/hour/direction) peak, 920 pphpd off.
These gondolas look like they can hold a max of about six passengers, but there's also a lot more of them. The article offhandly mentions a peak headway of thirty seconds. This implies a max capacity of 720 pphpd peak. For the same max capacity as current Blue Line service, we'd need to land a gondola every 15 seconds. The catch is that the Blue Line still has room to add trains, but landing a gondola every 15 seconds is probably pushing it.
I was expecting this to turn out rather poorly in the gondolas' favor, but considering the major advantages in capital cost, this actually doesn't look too bad. And they do have a point about high-frequency services attracting ridership. The main question is whether they can actually pull this off for the stated capital costs, and whether the operations and maintenance costs will come back to bite you later.
Gondolas, like elevated monorails and trains, have an unfortunate failure mode which is 'stopped and trapped' so in the event the system has to stop, everyone is 'trapped'. Back in pre-historic times when Disney ran their 'people mover' (which finessed the load/unload option quite well with the moving platform, one load/unload every 10 seconds) they talked about systems with excess cable such that in an emergency the gondolas could all lower to the ground. But that is impractical in longer runs (the wire buffer needs to be too long) and has its own issue if it lowers the gondolas in a non-emergency situation.
The best things they have going for them are that you can easily re-use existing right of way, and the per-mile implementation costs can be lower than conventional light rail or subways.
My favorite system that was spec'd but never built was the Chicago PRT (Personal Rapid Transit) which had four person 'cars' on a track that worked like elevators. You pushed a button at the track and an empty car arrived, you got in and punched your destination. It didn't have to stop until you got there. That particular system had issues with the amount of computer power it needed, although today it would be trivial to implement. If you can imagine autonomous vehicles on a track with 'smart' switches, its a lot easier than a self driving car.
What if we added a rolled-up rope ladder inside each gondola? Also, if they are laid over the existing road network, in the case of major failure you could have the fire department rescue the people who can't climb down a ladder on their own.
The way the "trapped" situation is solved for large Ferris wheels is a secondary spool of cable that you can attach to a truck and propel the system for long enough to evacuate it. That strikes me as applicable here.
In ski resorts, having to rescue people in stopped gondolas is an extremely rare event. I wonder what the fatalities per kilometer per passengers are, but I wager they are lower than urban bus transportation.
Looks like you have not been in a large ski resort lately - throughput of common cable transportation is at least double the 720 pphpd you estimated. There are now 40 years of experience in increasing cable car throughput. As urban transportation, Medellín and Caracas put 3000 people through per hour in each direction. The Rheinseilbahn in Koblenz gets 3800 people per hour across the river in each direction. 6000 people through per hour in each direction is nowadays considered within reach of the current technology.
"the Rheinseilbahn ("rhine ropeway") can move 7600 people max. per hour in both ways, that's a world record at the moment. It connects two parts of the city across the river rhine. "
These gondolas look like they can hold a max of about six passengers, but there's also a lot more of them. The article offhandly mentions a peak headway of thirty seconds. This implies a max capacity of 720 pphpd peak. For the same max capacity as current Blue Line service, we'd need to land a gondola every 15 seconds. The catch is that the Blue Line still has room to add trains, but landing a gondola every 15 seconds is probably pushing it.
I was expecting this to turn out rather poorly in the gondolas' favor, but considering the major advantages in capital cost, this actually doesn't look too bad. And they do have a point about high-frequency services attracting ridership. The main question is whether they can actually pull this off for the stated capital costs, and whether the operations and maintenance costs will come back to bite you later.