Idk much about recycling but they do get frequently frankincense, its called retread/recap.. and its garbage, but its like 50% of the replacement tires out there.. sometimes they pop and fuck up other vehicles on the road even without a wreck..
And there's lots of shitty mom&pop retreaders that just stack tons of old tires outside their shop in a big pile, even though just one old tire by itself is capable of spontaneous combustion, particularly when left in the sun.