It's not gonna happen. The majority of people who pay would find 18% tax as an increase. They would also find 18% tax as a decrease for the rich. And the real estate lobby would not allow no mortgage deductions.
Guess you missed every post before yours since you still think that tax brackets are an accurate measure of what people are really paying. I'd gladly by 38% taxes if I could only claim 6% of my salary/other income as "taxable". Brackets are meaningless in a world of deductions and tax breaks aimed at investments and business dealings. Why return to "who's on first" when we already made it to "i don't know" on second?