One critique is that this assumes immediate pass-through of payroll tax increases to the worker, but doesn't include, so far as I can tell, anything about valuing my employee-provided health insurance, which would presumably be replaced by an equal value in wages if we did get a single-payer plan. Sticky wage concerns probably apply equally to both sides of this equation, so this is a little bit tricky. I tend to agree with the people who say this is not a great way to understand and analyze Sanders's proposals.