So, whose assumptions do we trust? The economist's or your's?
How bout, not using stock assumptions, neither an economist's stock assumptions nor your strawman assumptions.
Instead go to an econometric model. Dynamic, empirically based models make alot more sense to me when evaluating the relative merits of systems than generic assumptions and static regressions that tend to be garbage based more in descriptive convenience or ideology than real world behaviour.
Parametrically match a know system to historical data series, then introduce the system changes to evaluate merit of the change.
Actually those are your assumptions, not his. When you quote people saying that all consumer goods are embedded with 30% of taxes in them, you are assuming all the taxes are in the price of the goods. So if you don't like those assumptions, blame your fair tax economists who spew those numbers.
Instead go to an econometric model. Dynamic, empirically based models make alot more sense to me when evaluating the relative merits of systems than generic assumptions and static regressions that tend to be garbage based more in descriptive convenience or ideology than real world behaviour.
Ummm, a tax system imposing a 30% sales tax has never been tried, so there is no empirical data for these so-called models, just assumptions by modelers who were paid for to make the fair tax look good.