“When I watched the tape of the tread collapsing it seemed to go clear to the rim.”
Yes. Just like a conventional tire. But probably with better survivability.
“But probably with better survivability.”
Maybe. But in an aired tire the rubber is not the entire cushion as it is never designed to take the jar from the blow. The air under pressure is. And as you cannot damage air that way, it springs back with an alternate amount of pressure. Each time you hit the rubber with the rim, there will be damage to the rubber. And depending on the amount of jar will depend on the damage to the tire on each instance. So a series of light contact or one big one could do enough damage to harm the tire.
rwood