Simply put, different tires are constructed from different compounds. The tread design may also be different but the compound of the rubber makes the biggest difference. A tire constructed with a very soft compound may very well hold the road better, ride smooth, and have more traction but it will also not last very long. A tire with a very hard compound may last a long time but ride rough, have poor traction, and handle poorly. All tires are a compromise between these two extremes. So the tire is designed for a specific application and purpose.
Clay