[ineptech]

> You don’t file a form with the IRS when you get married, have a child, divorce, pay for daycare...

Er, yes you do? I'm pretty sure all of the things you listed are explicitly included in the 1040 and associated tax forms we have today. Daycare expenses, for example, are supplied in form 2441: https://www.irs.gov/forms-pubs/about-form-2441

This seems like pure FUD. The claim isn't that easy file would work for all people, the claim is that the present system is needlessly opaque in a way that benefits only the tax prep middle-men. More generally, it's really hard to claim that the US can't possibly accomplish something that many other countries already do.

[twoodfin]

The claim was that the IRS had all this information for most Americans without the content of the 1040’s they have to file today.

[ineptech]

You're interpreting "tax liability" to include every possible deduction, when I think it's perfectly clear that OP was referring to taxable income before deductions.