Actually, Marx was saying the exact same thing about machinery unemploying people that HN is saying every now and then(I don't have a firm opinion on the matter, I just found it amusing to read the same argument made 150 years ago; Marx actually credited a whole slew of other economists with making this argument.)
The quote (from https://www.marxists.org/archive/marx/works/1865/value-price...):
"...one might infer, as Adam Smith, in whose days modern industry was still in its infancy, did infer, that the accelerated accumulation of capital must turn the balance in favour of the working man, by securing a growing demand for his labour. From this same standpoint many contemporary writers have wondered that English capital having grown in that last twenty years so much quicker than English population, wages should not have been more enhanced. But simultaneously with the progress of accumulation there takes place a progressive change in the composition of capital. That part of the aggregate capital which consists of fixed capital, machinery, raw materials, means of production in all possible forms, progressively increases as compared with the other part of capital, which is laid out in wages or in the purchase of labour. This law has been stated in a more or less accurate manner by Mr. Barton, Ricardo, Sismondi, Professor Richard Jones, Professor Ramsey, Cherbuilliez, and others."
(I personally am not a huge fan of Marx's writings, mainly because of the strong contempt for humanity that I feel emanating from them... incidentally I've recently stumbled upon this one, though.)
A scary analogy in favor of this argument is, a horse cannot economically perform almost any job today, hence most were slaughtered though few were kept for amusement. That happened after horses had a very good run where every improvement in technology increased "horse employment." If a machine exist to outperform a human in any conceivable job, it's not very different (and then you get to the discussion of the political options.)
A counterargument is that up until now this argument was wrong many times, and that we're very far from an AGI, or even from machines beating humans at every possible task.