the claim that intelligence explosion is likely to occur within the next 150 years

"We have made little progress toward cross-domain intelligence."

That is, while human-AI comparison is turning to the advantage of AIs, so-called, in an increasing number of narrow domains, the goal of cross-domain generalization of insight seems as elusive as ever, and there doesn't seem to be a hugely promising angle of attack (in the sense that you see AI researchers swarming to explore that angle).