In a thousand years from now, I honestly think 100PB is small for a thumb drive. I've seen such drastic increase in storage density in my lifetime that, while I don't expect it, I wouldn't be surprised if I see 100PB in single storage devices at some point in my lifetime.
I'm already dealing with PB-sized storage clusters at work, so the need for that k8nd of storage is already there, and necessity drives innovation.