You do realize that the IRS already gets a copy of your W2, 1099s, 1098s, etc, right? You can order up a transcript of the data that the IRS has on your file for a given year and they have a pretty complete set of data from all the various mandatory forms.
What they don't have (and can't have, because only you have them) is data you'd need for schedules C and E and much of the deductions for schedule A. Guess what? Intuit and your local "tax guy" don't have those either, unless you give it to them.
I worry more about the tax law changes that might come if people started paying EVEN LESS attention than today about how their taxes are calculated than I do about the IRS ability to execute this.
Clicking a webform and getting a bill or direct deposit divorces people from the fact that this is real money in play.
But at the same time, the IRS has no real competitive alternative to something like TurboTax. Sponsoring the creation of yet another tax-preparation software feels like XKCD Comic number 927
At $50 for TurboTax (which is still more than the $20 I pay for TaxAct), its still an adequate solution that beats the current status quo.
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So my question to you is: do you not realize how bad the status quo actually is? The average preparation cost is $200 according to the IRS, which is very far above "TurboTax Deluxe edition", and far far above any of the other 3rd party tax solutions.
If people would prepare their own taxes with TurboTax, life would in fact be better than the current state. Period.
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Now we can imagine the IRS creating a website and everything will be Rainbows and Unicorns, but lets not forget about the Obamacare website. Turns out that competent web-developers are expensive, that government employees aren't competent web-developers, and finally aren't even that competent at figuring out contractors.
I can imagine a future where the US Government raises wages for once, builds out some competent project managers, retains talent, attracts talent, finds a contractor who can help them develop this hypothetical website, and then hope that the next $500-million+ web-project is actually successful.
Or... you know. I can just recommend people to use TurboTax (or TaxAct). Which already works, and is better than the status quo.