Again, for 80% of filers,
none of this matters. They have their one W2 and take the standard deduction. The only thing the IRS needs to know is what's on the W2 and their marriage status, which they absolutely do have because if you get the marriage status wrong they send you a letter (and it's a matter of public record anyway).
So for 80% of people, they would never have to fill out a tax form at all. They could just get the tax bill and have it auto-pay (or more likely auto-refund).
And for the next 10% of people, who only take a small set of deductions that you can take on top of the standard deduction, you don't need even a two page form, you just need a wizard that asks a few questions like TurboTax.
And then for the rest they can opt to fill out the regular forms if they don't agree with how the IRS calculated their bill. This is how it works in pretty much every other civilized country (and a lot of uncivilized ones too).
So for 80% of people, they would never have to fill out a tax form at all. They could just get the tax bill and have it auto-pay (or more likely auto-refund).
And for the next 10% of people, who only take a small set of deductions that you can take on top of the standard deduction, you don't need even a two page form, you just need a wizard that asks a few questions like TurboTax.
And then for the rest they can opt to fill out the regular forms if they don't agree with how the IRS calculated their bill. This is how it works in pretty much every other civilized country (and a lot of uncivilized ones too).