To which I could then add a (5): the laity finally work out what’s going on and revolt; either to help form new movements, or as individuals to wander off into church traditions very different to what they have come from, but which don’t have the faults of where they have come from.
In my home context, I used to joke that it was far easier in New Zealand to find a Bible-believing Catholic than to find a Bible-believing Methodist, which as a movement lost its grip precisely in the way you describe.