Except that it isn't.
First, to implement a prebate, you would have to track down and inventory every person in the USA. You would have to determine their legal status. How would you handle households of people, married people, etc. The fact that our government can barely do anything is going to open this up to fraud. On top of this, how are you going to do this without a massive federal bureaucracy, like the IRS? Heck, there's already a schedule for varying prebate amounts based on what type of household you have. How would that schedule be subject to any less of a "lobbying feast" than my suggestion?
Second, what if $X is enough to cover basic needs in low cost states but not high enough to cover those needs in high cost states? You end up with low income people in high cost states being screwed. If the prebate is too high, then people in the low cost states get what amounts to a welfare check from the government.
Third, what if a president decides that if you do not agree with his particular pet policy, you don't get your prebate? We already have the same problem with 0bamacare and tax refunds.
I understand the merit of the arguments for the prebate, but I just don't think it is workable in a practical sense, for the reasons above. Besides, why don't states which have sales taxes use prebates for their sales tax?