They need to remove old seasonal content to make room for new ones. Servers run out of room too. As for keeping the ovens locked, they are goal ovens. Unless you were lucky enough to start playing since the game was launched years ago, you would always have locked ovens/recipes. I've been playing for 2 years and have some recipes locked. I'm annoyed like everyone else but I get the reasoning behind it and so don't see the point in constantly complaining about locked items.