No one can predict the future. Really, no one. Sometimes there is a hit, sure, but mostly it is a miss.
The other thing is in their introduction: "superhuman AI"
_artificial_ intelligence is always, by definition, different from _natural_ intelligence. That they've chosen the word "superhuman" shows me that they are mixing the things up.
I think you're reading too much into the meaning of "superhuman". I take it to mean "abilities greater than any single human" (for the same amount of time taken), which today's AIs have already demonstrated.
The other thing is in their introduction: "superhuman AI" _artificial_ intelligence is always, by definition, different from _natural_ intelligence. That they've chosen the word "superhuman" shows me that they are mixing the things up.