The plot requires that every person in any position of decision making authority on earth be an absolute pants-shitting moron.

That's not entirely fair. It requires that people became overly reliant on technology to the point where it became an evolutionary trap rather than a material benefit. It's not out of line with the end of "I, Robot" in which super-intelligent computers effectively render human administration obsolete without humans realizing it, because the computers are tasked with optimizing humanity and human decision making just gets in the way. Watts's augmented humans, vampire adjuncts, and AI assistants all end up pursuing their purposes too well. And the alien probe-thing they discover at the edge of the solar system suggests a future end state for humanity as much as a possible first-contact scenario.

The hypothesis he puts forward, between Blindsight and Echo Praxia, is that evolution ultimately favors instinctive response over rational self-determination. Humanity's brief 10,000 year flirtation with consciousness is an accident of evolution that the next epoch of biological change will undo. Human decision making is a feature we developed because we lacked predators to exploit it. As soon as we re-introduced predators to our ecosystem (sociopaths like the main character and his crew, resurrected monsters, unregulated machine intelligence, actual extraterrestrials) we were as done for as the Dodo.