[srdev]

I think that depends on how much mining hashing power scales with regard to transaction rate. From a technical point of view, there's no reason that the hash rate has to increase to process more transactions. But from an economic and game theoretical point of view, increasing transaction rate makes the network more valuable, which makes attack rewards more valuable, which necessitates a higher hash rate. I'm not sure anyone has sussed out what the relationship is between transaction rate and minimum necessary hash rate.