> This demand externality traps rational firms in an automation arms race, displacing workers well beyond what is collectively optimal.
you can't be trapped in a sub-optimal situation and be rational at the same time. the rational thing for these rational competitors to do would be to agree to slow their deployment of ai, because the cost savings will be more than lost to demand destruction down the line. so if they won't or can't do that, they aren't rational. on the flip side, if it is actually impossible to slow ai deployment, then the firms are rational and the situation they find themselves in isn't actually sub-optimal.
it's irritating to me because i often see persuit of self-interest even to one's eventual detriment held up as "rationality", which may be true in some technical sense within the field of economics (i really couldn't say), but is certainly not true for, like, actual rationality. myopic selfishness is never rational.