Just because you haven’t seen it, it doesn’t mean it’s never happened.
I’m not disputing that rides don’t operate perfectly all the time. They don’t. It’s definitely possible that everything is working 100% when the CMs open the ride and so a show check in the morning, and then as the day passes, something stops working. That’s normal and happens a lot. What I’m saying is that Disney, at least when I worked there, used to take care of the problems within a timely manner, sometimes immediately when it was feasible and realistic, and would not let the problems linger for days or weeks or months.
I’m a previous Attractions CM. I’m speaking from personal experiences. I was trained that all animatronics had to be working for show to be acceptable. Each dark ride has unique show elements (for example, the fireworks and twinkling star in Pinocchio), but 100% working animatronics was one show element that was consistent throughout all the dark rides. If the CM doing the morning ride-through noticed that Pinocchio or either of the dancing marionettes were not working, or any of the other moving animatronics, they reported it to the lead, who would then call maintenance to come and fix it. The ride wouldn’t open. Maybe the Fantasyland standards were higher.