Absolutely would not work in the US (as, unfortunately, most public services). There's already a huge lobby from TurboTax and other players. All countries that got to this level of automation already had publicly developed, free software for tax payers previously.

How did you sleep last night? Your cynicism is slowing.

Just this year, the IRS started a direct file pilot program that flies in the face of "it absolutely would not work". It's not everything, but it's a start.