Arguably, some people are already not economically viable as employees. But I don't know why most of people wouldn't be able to adapt, just like their no-longer-economically-viable peasant ancestors did.
Until now, humans always had multiple competitive advantages in sensing, intelligence, and motor control, and an integrated system for all. That competitive advantage made them the best adaptable machines available.
That advantage is going away, particularly for the less intelligent and less educated.
Horses used to compete for real work in the economy, and win. Their population dwindled in the US as they were competed out of the marketplace by machines. Horse genocide. Their domesticated population has been coming back, but now as pets more than workers,...
I really like this argument for UBI, it looks at the real problems on the front lines of current problems with existing programs.
Something has to be done about this, none of those manufacturing, or managerial jobs are coming back, and the minimum wage increase movement is going to really hammer youth and the un-skilled. Those are the easiest to radicalize, and once they get really angry, things could get ugly very quickly.
"because they aren’t publicly acknowledging just how poorly our present means-tested programs are targeted by virtue of their applied conditions, and just how unequal one dollar can be to one dollar, however counterintuitive that may seem."
"The fact is that cash welfare, as it exists today, is not given to the overwhelming majority of those living in poverty who need it."
https://techcrunch.com/2016/09/09/the-progressive-case-for-replacing-the-welfare-state-with-basic-income/