I think basically at any one time there are a lot of competing new-born technologies, and it's only in retrospect that we can see which of them will go exponent

I think basically at any one time there are a lot of competing new-born technologies, and it's only in retrospect that we can see which of them will go exponential through a feedback cycle of improvement and growing adoption. It's not so much that technology always goes exponential. It's that in retrospect, we notice the ones that did.