Bill Gates says robots that take your job should pay taxes
businessinsider.de
businessinsider.de
And because most of those profits will accumulate within a small segment of the population, it's not possible to tax the profits indirectly. Not enough will trickle down.[1] And it's politically difficult to increase taxes on the super rich much more than we already do. Taxing financial instruments--which is where the rich move and grow their wealth--is problematic. Taxing income and assets at a point where they're readily identifiable and easily enforceable is the most efficient and most equitable.
Plus, there's ample precedent in terms of personal property tax. Most basic example: some states tax cars. That's probably how a thing like this would be implemented--not as a type of income tax, but as a property tax.
[1] Lower prices of goods and services notwithstanding.