I think they only do that during the time that they are active with the game. They don't want others to take credit for their work, which is completely understandable. It is morally wrong to do so. If the author has abandoned it then they likely have no further interest in the game or even care about it anymore, and some of them aren't going to see any request for permission to update it either. I think there should be a time limit on that rule, especially if the person who updates it has made an attempt to contact the author and hasn't gotten a response, keeps the original author's name on it and lists it as an unofficial update. (i.e. "Yellog's Dark Wood and Cream Furniture unofficial update")