Yes, tires will become lighter in the future if we compare the same size. The trend in the industry is generally towards producing lighter tires without compromising durability, safety, or performance. The introduction of advanced materials, such as aramid fibers or new rubber compound formulations, will aid with that significantly.
Additionally, with an increasing global emphasis on fuel efficiency and reduced emissions, the incentive to produce lightweight, low-rolling resistance tires continues to grow.
However, tires are also growing every year. If 20 years ago, the largest tires for passenger cars were 18-inch tires, and now some reach 23 inches! That is largely because large SUVs are becoming more popular, which require bulkier tires.