Bill Gates' suggestion on robot tax won't work!

http://fortune.com/2017/02/18/bill-gates-robot-taxes-automation/
Imposition of robot tax to save any human job won't work because it is a regressive action that will impede productivity.  This action will force businesses to choose between human or robot based on cost instead of productivity.  Furthermore, businesses will move to other countries without robot tax so that more robots can be used.  The fundamental reason businesses adopt automation is to improve productivity and lower production cost.  If we impose robot tax to compel businesses to adopt lesser robots, it will defeat the purpose of improving productivity as a human cannot work 24/7.  If full automation can increase productivity and lower product cost better than semi-automation with some human labour, why would we want semi-automation unless full automation has a higher robot tax which can lead to higher production cost?