As I mentioned, the manufacturers will need to spend money on R&D to develop alternatives. Right now the tire manufacturers don't have any incentive because there's no financial benefit.
Even though consumers don't have a choice when they buy tires today, other products have cleaner alternatives. If I was a manufacturer of tires and saw consumers consistently choosing cleaner products when possible, I would have an incentive to see if I could reduce the pollution, because I would gain market share. The first manufacturer would sell more tires and others would need to follow. Not enough consumers make this choice today to make up the cost of new technologies.
Theres no need for R&D. Real rubber tyres are environmentally friendly as the abrasion particles are natural. They are much better performing in terms of grip, but just more expensivce to produce.
IIRC the military use real rubber tyres still because of their longer life and better performance.
If people were willing to pay more for their tyres then this would be a non issue.
Pure natural rubber has poor ozone resistance. It will need stabilizing additives, and at least one of these (6PPD) has been found to have toxicity problems.
Even though consumers don't have a choice when they buy tires today, other products have cleaner alternatives. If I was a manufacturer of tires and saw consumers consistently choosing cleaner products when possible, I would have an incentive to see if I could reduce the pollution, because I would gain market share. The first manufacturer would sell more tires and others would need to follow. Not enough consumers make this choice today to make up the cost of new technologies.