“Have kids? Tax exemption. Invest? tax exemption...”
Buy a house - exemption! I honestly don’t think home-owners will ever give theirs up.
No doubt it would be a tough sell but it could be sold. Those are deductions so it is not a dollar for dollar return. Withholdings would be gone. Tax preparation fees gone. Cost of all goods and services down from removing tax pass alongs. No fear of audits. Reduced government spending for IRS salaries and expenses. Many more plus and minuses I cannot hope to cover here but enough I believe to make the case.