Um yeah, government spends too much, we know. But given that government needs to exist and spend some amount, it needs a way to collect taxes. The income tax is a spectacularly bad way to do that; the FairTax, while not perfect, would be a substantial improvement.
If the government ever gets around to passing your tax, you can bet it will raise revenue for the government higher than what they realize now. They'll always find a need for a surcharge to the base rate or a deduction or an exemption and pretty soon it will be worse than the present system.
Why encourage the government to find another way to tax us?