One of the last visits we had down to WDW, a transportation CM stated Disney was having more issues with the Monorail as it gets older. The main problem is it is nearly impossible to perform a major overhaul due to parts sourcing. I guess it has to do with the manufacturer is no longer in business or no longer handles the parts. While waiting at a park for people to load, a bus driver once told me if a bus goes out of service it's no problem. Disney has spares in the system. A back up bus gets put into the service. Need extra service capacity no problem. You can call in drivers and more buses can be pressed into service. With the Monorail my assumption is not so much. What is there? 3 maybe 4 trains total.
As for the gondolas, I don't know. Nifty idea. I don't know if I want to be 100 feet in the air if they stop working. It's not like they can pull another one and everyone can load up into that one and continue on. Quite frankly there really is a bevy of transportation options when it comes to WDW. Boats, Buses, Monorails, Gondolas, people movers, trucks, minivans, and even trains inside the park itself. It's pretty interesting.