While that's true, even contributions can contribute to the burnout, especially when they are made without any input from the maintainers.

The classic "massive PR that changes how something fundamentally works" comes to mind. And while I'd hope i'm not going to do something quite that big, throwing a bunch of code at them and saying "put this in?" feels much worse than asking. Not to mention that it will end up being a waste of my own time as well.