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.