I think you somewhat missed the point that fox is getting at here. If I read her correctly, one of the problems that she is running into with that is the fact that all the savings that Mr. and Miss. Fox have acquired throughout the years has been subject to an income tax and NOT a sales tax. IOW, she has ALREADY paid for the government. By instituting a national sales tax and no income tax you have essentially shifted that burden BACK to her and are requiring her to pay taxes essentially twice – once on the income as it was earned and already paid and now a second time when she uses it. Such would essentially be a punishment for anyone that actually bothered to do the right thing and save some money for retirement.
With regard to SS income, that is going to be taxed via income tax anyway, so if the sales tax replaced personal income tax, that change should be a wash.
With regard to savings... my 401k is pretax money, I believe IRAs are also pretax money, so in theory pretax savings that become income would be taxed as income anyway no? Thus the income tax from the pretax savings systems would also be a wash in the change to sales tax.
I suppose for people that have after tax savings, that are not taxed as income then yeah for that money, such as Certificates of Deposit and Inherited money that has already gone through probate, yeah I suppose for already taxed assets, such as my home, my car, my savings etc. when those are taxed again as sales then I loose out by being taxed again.
That said most "large" investments have a return on investment. Most large savings eventually grow to a size where it starts earning a return on investment that is significant. Those returns on investment are typically taxed as capital gains. So again if that is converted to sales tax it should be a wash.
Thus one would have to argue that they have a large nest egg that has already been taxed, and for which there is no short or long term capital gain taxes or further personal income taxes and/or penalties to be applied on withdrawl (aka capital basis). Such as that may be the case, in that circumstance I could see the system for changing over from income to a sales tax system that would allow that particular money that was void of income tax, when spent, to be void of the federal portion of sales tax since it is an asset that is apparently void of federal taxes.
Note: This is the rough equivalent of deciding not to tax the rich for the assets they already have when they spend them, because they already paid taxes once on that money. I'm good with that but I doubt you'll find any democrats who agree to not tax the rich. The argument will simply move from current tax rates in which the rich get a discount (because its not personal income its capital gains) to sales tax rates that the rich get a discount for because they are using money that was previously taxed.
For me half my 401k is currently gain, not basis. I hope by the time I retire, 2/3-3/4 of my 401k will be gain not basis.