An income tax diminishes income. There are many examples of this. This was one reason why Reagan became a Republican, because of high marginal income tax rates that were affecting him. Look at Europe's high rates, and how the US is (comparatively) better off.
A sales tax diminish sales. There are many examples of this too. Look when (New York state?) reduced the sales tax on clothing. Sales increased dramatically. Look at the difference between Oregon and Washington. One has an income tax, one has a sales tax.
A 23-30% sales tax will DEFINITELY hurt sales. To not understand that woefully underestimates incentives/costs and people's/consumer's/taxpayer's reactions.
Since you did, though, here was my answer from that thread:
Keep in mind that prices will be reduced prior to the FairTax being applied and then be increased back to around what the were and you will have more money in hand to buy things with - no income tax, receipt of the prebate, a wider tax base with consumption rather than income, and a greatly expanding economy. Since the FairTax is revenue neutral there will certainly be little or no overall damage to consumption. The basic revenue amount is the same, it is being obtained differently ... BUT the tax will now apply to a part of the tax base that had not been taxed before to any great degree - the illegal economy. Rather that hurting sales these things should, along with an expanding economy, greatly help sales.""I believe that you are not considering the entire tax dynamic when you say that the FairTax will hurt sales.