For the goals of Tesla and Elon Musk competition IS a good sign. Because goal is to accelerate the turn over to environment friendly cars and sustainable energy. So every competition is a success.
Tesla don't has to become 100 years old. Well it would be bretty nice and if tesla disappers too early it would be worse for me too as a Tesla owner. But to achieving the turn over it's not neccessary to stay forever. Just make enough rumor to the other car manufacturers.