Maybe, but over all of human history new technology has never taken away employment- it has always changed its nature while increasing productivity.
That's a pretty contentious claim. You can safely say that new technology has never taken away employment permanently. Or at least long term. The people made unemployed by new technology eventually found new employment, or at least their children or grandchildren did, but short-term automation would often absolutely lead to overall increase in unemployment. And just because permenent reduction in employment has never happened in the past doesn't mean it can't happen in future. There's always a first time for everything.
Besides, the binary employed/unemployed distinction isn't the only important one, the type of job you do is just as, if not more, important. Working some kind of job almost always beats being unemployed, but there is a huge difference between a comfortable respectable middle-class job that can pay for a house, a car and support your whole family and a minimum-wage or below McJob.
The 'increasing productivity' bit is also more complicated than that. How easily you can manufacture a good or provide a service (and usually consequently how cheap that good or service becomes) is only one variable. Another one is the quality of that good or service - and that can obviously be subjective, but often it's pretty objective. Hand-produced nails are no more valuable than machine produced ones (less valuable normally, because human will make mistakes and won't be able to reproduce the required shape perfectly every single time). But with food for example, as you start to add more and more automation and chemicals at some point quality and effect on health can start to go down. Then food produced with less automation can become a premium product.
As far as art is concerned, the desirability difference between human art and mass-produced AI slop is pretty obvious. Besides, even before AI we were already getting way more art than we could possibly consume, and so human art was never that expensive (unless it was collector high art). The phrase 'starving artist' exists for a reason. So increase in productivity doesn't produce that much benefit here, whereas decrease in quality is certainly a huge drawback.
Having said that, 70% of middle class jobs being replaced in last 45 years due to automation does seem like a very dubious claim. It probably depends on how you define a 'middle class job'. Also, if automation replaced one middle class job with another comparable middle class job, would that also count?