No one is asking that Amazon pay a vastly higher salary to their low tier employees, only that they consider the cost of living for those employees and pay accordingly within a particular market.
The means to afford food and housing should not be out of reach of a full time employee, even if their position is likely to be automated in the future. That shouldn't be considered a luxury only available to the well-to-do. If the likelihood of automation is a valid rationale for lowering wages then just about everyone should be living on borrowed time and $12.00/hr.
And Amazon is pushing for full automation at maximum speed regardless, so employee wages are likely not a factor in that timeline.