Actually automation is replacing the work that humans have to do - this means that most activities left will be the ones that are not in high demand, with low or no pay. Imagine we have machines providing us food and all the material possessions we ever need, without any human input. Traditional capitalism/distribution of wealth through employment makes little sense under this scenario.
This model of taking from the productive sources and rewarding everyone else will have to break at a certain point. how come you get rewarded for enjoying the gossip column and I spend extra effort doing something else which is harder and my earnings are taken away?
a) The "productive sources" are mostly automated. b) you also get rewarded since the basic income is universal. whatever work you do provides you with extra income - people who work hard will still be rewarded accordingly.