I'd guess because Stross tends to be a very pragmatic / utilitarian sci-fi writer.
We suspect its going to be a thing, but nobody really knows what the death of human employment will mean, or if it will really happen. If it does, its probably much more of a black swan than "the internet of things", but as he noted with cars, sometimes things you discount end up revolutionizing the world, and stuff you thought was a killer, because of short range performance, ends up bland in the long run. Its kind of like stocks, everybody wants to buy FB or Google after they change the world, but its a whole nother story to figure that out beforehand.
You can guess that the death of employment for pay will be a huge event, but to say much more you have to start committing toward one of many possible paths beyond your event horizon. Maybe a revolution as robots steal our jobs, maybe boring and mostly like today, maybe endless freedom to create, or kind of pointless (cause we're all VR slaves or some other such thing)). The slope's there, but we can't see over the hill.
Aside: I dig that the later half reads like a love letter for one of my favourite, and one of the more durable languages out there. Almost 30 years and Perl's still quietly chuggin along.