Traction is not the only factor. How does this new tire affect steering? How much noise does it make as it rolls on the ground? How much noise does it make as air flows over it at high speed? How durable is it? How does it handle high rotational speeds? How does it handle impact? How does it handle braking? How does it handle different weather and road conditions, different temperatures? How does it treat the road surface? And can it be manufactured at such huge scales? There are plenty of reasons why it might very well be completely unsuitable as car tires.