If the proceeds weren't concentrated in few hands we could all benefit from mechanisation and the consequent increased production. As it stands, automating is plainly a direct threat to workers.
But there will be new sorts of work, at least partially in areas that we can't even think of right now, and there will also be increased leisure time. As long as we don't run out of natural/real resources and/or habitat (a BIG BIG if, mind you, and something I do feel legitimately pessimistic about- hard physical constraints to growth are a real thing), we'll find a way to muddle through.
What on earth makes you think that?
Well, that has generally been the trend over time- toiling as a shelf-stacker in WalMart for 29 hours a week (because any more and they'd have to give you health insurance) is less work than a 40-hour factory job is less work than constant tilling of the fields centuries prior. Mind you this is not to say, at
all, that the shelf stacker is better off than the factory worker*, in relative terms of course they're very much not, just that they have more free time.
And, also, a lot of this increase in time off is hidden in trends like people going to college, or even just finishing high school, and entering the work force later, which doesn't necessarily
seem like leisure time but counts when viewed from the simplistic econobot lens of "non-productive time". And,
and, the numbers that say we've had increased labor force participation over the past few decades from women entering the workforce, ergo less time off, conveniently forgets that the old expectation of "mother and housewife" was
itself one long, underappreciated toil. The actual supposed decrease in overall leisure time from that trend is very much illusory. (Yes, I'm aware that entering the workforce doesn't mean that mothers can shed their parenting toils- but various technological advances, chief among them washing machines and contraception, have indeed lessened that toil
greatly.)
* Though I'd personally take a nice hefty pay cut to live today as opposed to 1960, with the Internet, and better advances in medicine, and less deadly soot and crime, as well as various other societal advances.
