A couple of years ago, NASCAR had a road race for the smaller cars. It was raining so they used the racing rain tires. The tires were about 7 years old.
Well, better than slicks but the rubber would have been hard.
Back then in the Goodyear days the sticky rubber was incompletely cured, so they continued hardening with age (and quicker if warm) newer the batch the quicker the tyre.
Warming thetyres at the last moment helped too.
We used to send our tyre guy to "help Goodyear unload their truck" and he made sure the newest date stamp tyres went on our rims.
Racer's edge.