That is party the reason. For a long time the parks were only opened for certain times and there were tons of people across the internet complaining when a ride was down for refurbishment during their vacation. Now (well the last 5 years until now) when people go and their favorite ride is down for refurbishment they complain at the parks and then get on line and blast how terrible Disney is and how they ruined their family's hard earned vacation because Its A Small World was done. This lead to a lot of patch work being done. Now I think we are seeing that patch work start to fail. Some of the older rides also just have an issue with parts not being available and having to be constructed. So part of it is the expectation of the crowds, the fact maintenance doesn't have much time to do what it needs to in between guest clear and park opening, no down time any more, and the fact rides are running at capacity more than ever before.
On top of all that the budget cuts are making it even harder. Some of these rides are over 20 years old and still run on 20 year technology so they will break down and often if they aren't refurbished. Other rides are also just due to guest ignorance. Some people think they should be able to do whatever they want to and that includes getting out of their doom buggies, getting out of their honey pot to chase a lost hat, getting off the people mover mid ride, etc which all cause E-stops and e-stops can take a bit before the ride gets going again.