Superb question.
I am tempted to simply ask, has not taxing people worked? That sounds impolite but it is the essence of my answer.
The reason that healthcare premiums will become more affordable when the employer paid healthcare premiums are treated as taxable income is that the people will begin to question the cost for the first time.
Until then all the people need be concerned with is, is it covered, cost is not an issue and it should be.
There are countless improvements available once the Constitution and Capitalism frees the market from government interference.
People can question it all they want. But it's either suck it up and pay it or do without. Your plan would increase my taxes by about $250 a month and that's about it.