That may be true in the short term but those robots aren't going to repair themselves or make more of themselves. Human beings will have to do that unless someone comes up with a major breakthrough.
Software is no different; I've coded many applications that have eliminated human labor. Obviously I still need to code them but the point is that the overall labor is smaller.
The huge issue is going to be robots displacing the low level human jobs...
* Burger flipper 1000
* Fryalator 950
* Pizza Kiosk 2000
* Johnny Cab
* ConstructUtron (builder of buildings, and welder of many standard joints)How many of you are engaged in providing a product or service that was inconceivable in 1800? I couldn't even describe what I do to an 1800 era person.
I.e. there isn't a fixed amount of work to be done.
Well, training and experience aren't free. You can't just show up and start welding things. There's apprenticeships or union schools or maybe you're lucky enough know someone with a welding kit, but you need to learn how to weld first. It's not entirely one of those artificial market barriers. Bad welds can create structural integrity issues and can be difficult to fix so they've got to be done right the first time. It's skilled labor, and skills take time to acquire.
These newly created jobs require some kind of capital to access. Could be just money to pay for education, or could be social capital of knowing the right people, or time spent learning the skill, but you're not gonna show up for the job. There's plenty of reasons why someone would have trouble finding that capital. Maybe they work to help support the family and don't have the time for education. There could be any number of reasons though that getting new skills is difficult, and there's no mail room for you to start in and work your way up to management. What happens when you can't afford bootstraps?
Also, as industries change or new industries are created, this can make it harder to transition to other industries if your skills don't transfer. You better have some savings or safety net while you retrain for a new industry if yours is collapsing. So, while I'm not sold that we'll have widespread unemployment, but I think it's more likely that social mobility takes a hit and the inequality gap widens.
There's some evidence that this is already happening and while more people are graduating the number of jobs requiring those degrees isn't increasing as fast, so higher skilled workers are pushing lower skilled workers down the ladder.
Not to mention that things are changing faster and faster (that exponential innovation curve), so changes that could wait for a new generation will need to be addressed sooner.
I mean you mentioned the print workers who were hand setting typeface until quite recently.
What did they do after their industry collapsed. Probably a lot of them became taxi drivers or took on other "equivalent" labor centric endeavors.
There might not be a fixed amount of work to go around, but there certainly is a fixed amount of vocations that people are willing to pay money for, and that displaced workers can reasonably be expected to move into... And that bell curve does appear to be being squeezed tremendously.
Of course there will always be people in the supply chain, but fewer. Maybe a lot fewer, in the long run.