I lived and worked in the UK for decades and never did my own tax return. When I moved to the US, the UK taxman spotted this, calculated that I had overpaid my taxes for that year and sent me a refund automatically.
I guess the reason why it's not done this way in the US is a combination of the general mistrust of government, and the lobbying from companies like Intuit to keep the tax system as complex as it is now.
I have to be nice about HMRC (the UK tax agency) as they were actually responsible for me making a chunk of money by refusing to make on a call on some options we'd been granted as the result of a ratchet agreement (which we'd actually tried to get removed from our first VC investment agreement!).
They wouldn't make a decision on how things would be taxed until after our IPO - so we were able to exercise the options and sell the shares to cover the worst case tax scenario.
After the IPO nice tax man said that the best case rules applied and we got to keep the money that would have been used to pay our tax bills.
"We are a member of the Free File Alliance, a consortium of private sector companies that has entered into an agreement with the federal government. Under this agreement, the member companies provide online federal tax preparation and filing services at no cost to eligible federal taxpayers, and the federal government has agreed not to provide a competing service.... However, future administrative, regulatory, or legislative activity in this area could harm our Consumer Tax business."
The lack of auto filing is not the core issue with our tax code. The ridiculous complexity is. I want auto filing but the tax code could be drastically simplified without the government directly competing with TurboTax.
There is an income threshold: $64,000 for 2016, which the IRS says covers ~70% of tax payers.
If you make less than that, the "Free File Alliance" let you submit a simple federal return for free using their software. They may try to upsell you on various things and may charge for a state return too.
Above that threshold, your only free options are the paper forms or the "Free Fillable Forms" online. The latter option is really simple. It will copy some numbers from place to place and does some basic math, but beyond that it is very similar to filling in the paper form--it won't help you optimize your return or anything like that.
I guess the reason why it's not done this way in the US is a combination of the general mistrust of government, and the lobbying from companies like Intuit to keep the tax system as complex as it is now.