You are right-that is the one and only big disadvantage. I would support a phase in of the NRST beside a phase out of the income tax but ONLY if a constitutional amendment was passed that said that after the year that was the last year of the phase-out that the income tax would be unlawful.
CG gave a very good response to this issue. There are many other good explanations on this thread as well. But the concept that you will lose 23% of your savings when the FairTax is implemented is based on a misunderstanding of the dynamics.the value if your savings under the FairTax is not likely going to be true. I think if you become more familiar with how the FairTax operates, and what it accomplishes, I think you will find that seniors with large after tax savings will fair better under the FairTax than under our current system.
http://www.freerepublic.com/focus/f-news/1332583/replies?c=484