I agree that we need to dramatically cut the size and scope (and therefore the cost) of government. However, nearly 90 years of the income tax has shown that we will not, and probably can not, accomplish that while we have a Marxist redistribution scheme (the income tax) masquarading as revenue collection. Too many people who do not perceive their true burden, or who are simply sucking at the teat of the productive, would have to be convinced that their "freebies" (which are anything but free) aren't worth the real cost.
Only under a single-stage, single-rate system (and the NRST proposals are the only ones that meet that definition) do individuals truly see what the real burden is. Only then can they be convinced that cutting government is crucial.
Additionally, revenue collection and spending are separate issues. The amount of revenue to be collected depends (albeit somewhat loosley at times) on the spending, but the method of collection is independent of that. Income taxes, by definition, require an invasive government agency to monitor private financial information -- as long as the tax law requires a determination of "income", we're stuck with the IRS jack-booted thugs. An NRST would dramatically reduce the invasiveness of the system and simplify collections by reducing the number of collection points by a factor of 10. The NRST also does away with the social engineering performed by the tax code.
No, the NRST is not worth fighting for. We have anger at the income tax, people see how much money is being extorted from them every year, every pay check for it. We should never replace it with a tax which cannot be estimated, cannot be seen, cannot be noticed. The income tax is smaller than the social security taxex. It is less than half the fed revenue and only about a quarter or a fifth of all the taxes people pay. However, they do not really know how much money they are being robbed by the other taxes so people don't complain about it. A tax which makes people angry is far better than a tax which people do not notice if we are ever going to get the government off our backs.