However - I think it is important to consider the political implications of such a future. It is unlikely that 50% unemployment is politically acceptable. If we were to move to a more communist / socialist society would robots still be doing the work?
It is unlikely that we all end up programming.
I think that we need to redesign society from a technological and _primatological_ standpoint because I think a lot of the extreme hierarchy and brutality we see in our world is a result of the way that our cultural frameworks handle our primitive needs such as various ways that men compete for sexual success (such as resource acquisition).
The thing that I think people are missing as a realistic concern or change is that by the time these robots are able to replace most human jobs, which doesn't seem like it will be too many decades from now, shortly after that, we have to expect that the robots will become even more capable than humans.
The robots will be smarter than people. Normal, unaltered humans will probably eventually be treated like animals. I think that people don't take this possibility seriously (to me it is a likelihood, and probably within my lifetime).
I don't think that means we should prevent the next 'species' from taking over, but I do think it means we need to plan for ways that we can integrate with super-intelligent technology in order to stay relevant. And I think that is going to be a very practical issue within a small number of decades.
It'll probably take us 50 years to have emission-free vehicles dominating the auto market, let alone robot overlords.
Maybe I'm just pessimistic (or optimistic), but I think Humans are too dumb and/or too smart to create an AI that will overthrow us. More likely, we'll ruin our society by overpopulating and draining our natural resources before we can prepare a suitable "Earth 2".
Or Zombies...never discount Zombies.
That said, strong AI is so difficult, and we are so far away from it, that it is likely that by the time it happens we will have automated everything else already.
I actually think social work will be the safest job. In a world filled with robots, people will want to talk to real people :)
The problem is really what do you do with a lot of people who need to do anything and probably don't need to exist? They tend to multiply quite rapidly as well as there is nothing else to do.
In a society that demands employment, 50% unemployment is a death-sentence. That's half your population draining the subsidies dry and raising taxes on the working half. Suddenly both sides are angry. Prisons become overburdened, people dead in the streets, Governments overthrown, CEO assassinations, etc.
Sure, in a fantasy land where things don't cost money and land isn't 'owned', 50% unemployment could be ok. Unfortunately that's not us yet.
Society is polarised by automation. The gap widens every day.
I've destroyed hundreds if not thousands of manual work positions over the years by making software that replaces them. I've now got to support the uenmploymed with my tax contribution. Welcome to the flawed turd-bag that capitalism is.