> I think the key idea that consciousness is a local maximum in the universe is fundamentally mistaken, if a cool thought experiment.
Very much agree, on both counts. Even "just" on earth, it's not like the more mechanistic approaches didn't have plenty of chances to compete. The near-instant and very complete domination by the first species to reach a certain level - and its subsequent orders-of-magnitude raising as it then starts to compete mainly with itself - was totally driven by evolution and there's no reason to think it wouldn't happen anywhere else. The only variable I can really see is in where it (evolution-driven intelligence increase) stops.
It's extremely hard to imagine even the basics such as group coordination and complex communication without some sense of self, and even the animals we see on earth with some level of these abilities demonstrate at least a proto-consciousness, which might well have won out in the end had we not been first past the post. There's no reason to think this phenomenon would be an earth-only anomaly.
It reminds of the "million monkeys with a million keyboards" thought experiment. Yes, they will, given infinite time, produce the entire works of shakespeare. But in the real universe they don't have infinite time, the actual shakespeare evolved, wrote it all first, then took over the monkey planet and enslaved or at least repurposed them before they even got the first paragraph out.
I don't mean to suggest that homo sapiens is some kind of universal peak of capability - we are almost certainly not - but I find it pretty much impossible to imagine sentient creatures being outcompeted by non-sentient ones under any circumstances.
It's expensive, sure, but consciousness appears to be a - the - superweapon, and whoeever grasps it first, wins.