Now, maybe you think it'd be quite useless, so you might suggest cutting away the crap and just paying people to do nothing. Congrats, you are now a proponent of basic income!
Economics is simply a game/system that shifts every couple of decades/centuries. Keep in mind the rules you're playing by can change at any time.
http://www.economist.com/blogs/economist-explains/2014/05/ec...
"From this history, Mr Piketty derives a grand theory of capital and inequality. As a general rule wealth grows faster than economic output, he explains, a concept he captures in the expression r > g (where r is the rate of return to wealth and g is the economic growth rate). Other things being equal, faster economic growth will diminish the importance of wealth in a society, whereas slower growth will increase it (and demographic change that slows global growth will make capital more dominant). But there are no natural forces pushing against the steady concentration of wealth. Only a burst of rapid growth (from technological progress or rising population) or government intervention can be counted on to keep economies from returning to the “patrimonial capitalism” that worried Karl Marx. Mr Piketty closes the book by recommending that governments step in now, by adopting a global tax on wealth, to prevent soaring inequality contributing to economic or political instability down the road."
Imagine the social unrest when a large portion of the populace is literally of negative value. It's not going to be pretty.
We need to start thinking now about how we're going to achieve a smaller but more elite population, so only useful people get born.
two: the metric you use to determine the value of a person is highly arbitrary, based on GDP, divorces are better for society than marriages, despite the fact that children going through divorces suffer in school and later go on to accomplish less, capitalism is generally too myopic to actually address any existential risks to the human race.
Now, why the heck would you (the farmer entrepreneur) care about what the government does with the taxes it generates from your revenues? The question is: is your investment profitable enough? Everything else about your scenario is politics and, in a democracy, these things are decided (or supposed to if you drink from the cynic's cup) by the population.
If the farmer (as a person) disagrees, he can just not buy or buy in another country or planet or whatever. A post-scarcity society has value enough for some of us that we'd run such an automated farm for little profit if only to selfishly sustain said society.
http://world.time.com/2012/12/14/what-if-the-worlds-soil-run...