That's a popular view, but only true for people who don't have any deductions, depreciations, business expenses, mileage, etc. For a large group of people, the IRS can run the math only after you submit the full list of inputs.
In sane countries, the "popular view" holds, as it should. Not so much in the US, though. The IRS knows how much I make, I want them to send me a form that says "we think you made this much, if that's true and you have no fancy deductions, sign here".
Then I just sign a form and return it instead of slogging through the bullshit that Intuit et al has lobbied for.
This doesn’t preclude the government pre-filling and giving you the option to amend. It would save everyone time, even the people who amend because some information would already be pre-filled.
You could always apply to a refund based on that information. But the government already has 99% of what is needed to file your taxes, they are just not allowed by the lobby of tax preparation.
