Because at the end of the day the Ferrari (or Porsche or Lamborghini) design is not a very comfortable or practical design for day to day use. The (two) people I know who own Porsche sports cars also own a second car.
Depends on the model. Panamera is definitely a daily driver type of car.
Sure, Porsche also makes more sensible cars. One of the people I know whop owns a 911 has a Cayenne as his day to day car.