"...A monthly rebate given in advance seems to imply the continued existence of an IRS bureaucracy that keeps track of how much income everybody makes. The rationale for the continuation of such an unnecessary and unwieldy system is cryptic to me...."
Under the current system, the price of all building materials is inflated due to entity level taxation. Once those costs are removed, the price of building materials should decrease...and with the prebate, your full paycheck in hand....you'll probably be able to buy the same house...
The only difference will be that you'll clearly see how much tax you are paying vs our current system where much of the tax cost is hidden from your view.
That's a much better answer. Presuming the best case scenario, that might make the difference.
But if the income tax is left in place (an admittedly different comparision), all bets are off.