Burn out, motive decay and the assorted problems you get when you engage long term creative endeavors are also a thing.That's called not having a work ethic.
People are changed by their work and time just as much as they change their work. So sometimes we grow beyond a project in a way where we lose any attachment and people tend to go on just by work ethic alone and that's when quality drops and people will start complain. Because the creative spark is not beholden to work ethics.
This is the nature of creative and generative endeavors. And we just don't want to let them die even though it'd be better. It's one of the main reasons why I advise people to make shit they can finish in a year.