A slight modification: though slow, they can have multiple un/loading points. The main gondola at Whistler has a mid-mountain loading point along with a top and bottom un/loading point. The Peak to Peak Gondola only has a loading point at each end because it's crossing a giant chasm.

Your point stands though: gondolas are probably not a great form of transport. That said, I have no idea what the speed limits would be for a gondola that was designed for speed.

They have those unloading points because they are able to take them off of the cable while loading and unloading. We don't design these for cities, but we could. This means loading/unloading could be coordinated across multiple nodes and you could even switch tracks which takes care of the fixed distance problem. Detachable chairlifts can do 12mph which is faster than many city buses. https://en.wikipedia.org/wiki/Detachable_chairlift

Detachable gondolas exist which means you can travel any length you want if you switch cables and have as many terminals as you want.

https://en.wikipedia.org/wiki/Detachable_chairlift

2000 people per hour per direction is a person every 2 seconds per direction which is not that far from a highway with single occupant cars. 1900 per lane is peak, but congestion is much slower. Speed is an issue, but larger gondolas can move more people fairly quickly.