The fundamental problem is that these desirable features are likely contrary to google's interests. They have convinced themselves that their recommendation system maximizes engagement, so anything that pulls users away from that is a pottential threat to growth of attention directed toward ads. They will tolerate these power-user style methods as long as they remain statistically unpopular among users. I seriously doubt they would willingly provide a button that negates the fruits of the targeting work at the core of their business model.