You miss the point completely: If Google ads an extra ad you might lose 20% of your traffic even if your rank stays the same. Or if they ad youtube videos on the display, or books, or local or whatever....
So call it manual, algorithmic, display change or whatever, you're f-ed and call moves more of web traffic to its own properties.
So call it manual, algorithmic, display change or whatever, you're f-ed and call moves more of web traffic to its own properties.