I don't want to get into all the other problems with uprooting the income tax, but here is the obvious reason not to do it:

It could be a diaster that could potentially bankrupt the whole fucking country. Securities markets (a huge part of our economy) would have so much unpredictability that things like mutual funds (you know those things that half the country is invested in) would be put in huge jeopardy. Agree or disagree with the principles behind the income tax, if you were to cease and desist the income tax, you'd be putting the country in a situation no one could predict. It could be the biggest financial diaster in history.

Any economist or financial analyst with any sense will tell you that if you want to change the tax structure in this country it would have to be very gradual. Cease and desist is way to much of a risk.