This will 100% happen at some point at Disney but it doesn't make me any less prone to ride the gondolas. No transportation is fool proof. I was stuck for ours on the Monorail once and I've been stuck in traffic countless times in my life.
Hopefully it won't be as long at Disney but as sure as the ocean is full of water we will see a news story, likely blown out of proportion, about guests getting stuck for some amount of time on the Disney Gondola system. Many pearls will be clutched.