Wilderness it better suited for larger builds. Not everyone can afford a town to hold these builds. Some new players stay out in the wilderness for a while until they can afford a town. Also, it's not as though the wilderness is overflowing with builds, there's plenty of space to explore and build yet. If the wilderness kept getting reset everyday, I could just memorize the coordinates of valuable items (temples, diamond ore, villages, etc) and just keep going back to them.