It is assuming that if the employer did not have to contribute that amount to the premium, that that same amount would be realized in the employees salary which is not true. It would stay in the employer's pocket.

Most economists regard employer contributions as an employee burden in the end. But then they also report that these benefits are a competitive disadvantage for US firms compared to overseas firms and (for example) claim that healthcare benefits add $1500 to the price of a car which cannot be true if they are deducted from salaries. They can't have it both ways. ;-)

It is certain that these costs are rising as a % of employee costs with experts confirming that middle earners already are seeing reduced quality of life issues with all but the highest percentiles joining that boat in coming years. Also it is reported that employers are buying cheaper plans by limiting choice and increasing co-pays which definitely transfers burden to employees. And we haven't started talking about the previously productive employees who lost their jobs in the recession.