Uber, public transportation, themselves, self driving cars.  The world is changing and teens tend to be the first to react since they don't have to change old habits.  If you live in the urban core we are already at a point where car ownership isn't 100% necessary.  Within 5 year I suspect that will be true for anyone in the metro, using car share programs like zip car or Uber will significantly reduce the need to own your own car.  Once those options are cheaper owning your own car will be a luxury but not a requirement.