The only equivalent plunge from genius I could think of was Ernest Hemmingway's tragic loss of ability to write. Hemmingway got up one morning and shot himself. Nicklaus got up the next morning and shot 66.
A few years ago we colonised this place with some of our finest felons, thieves, muggers, alcoholics and prostitutes, a strain of depravity which I believe has contributed greatly to this country's amazing vigour and enterprise.