The issue is the government doesn't and shouldn't know every possible detail of your life so if you're in a complex tax situation (most people aren't and can just take the standard deduction) you'd still need to do the preparations. But for the vast majority of people the government does already know what you're taxes should be because you're just taking the standard deduction which 87% of people did in 2018 and that number has grown slightly since then. [0]
For more complex cases where you have more deduction and income sources the government doesn't really know all the individual setups you may or may not qualify for and they only audit a small percentage of filers every year.
The reason it's been blocked is a mess of ideological and economic. Ideological from people who interested that want to make taxes more annoying so people are generally more anti tax and then they get elected and make cuts to the top percentages/businesses permanent while the tax cuts for the majority of citizens are temporary. This sets up a debt crisis when those 'temporary' cuts are also extended they can use to leverage for government cuts. On the economic side there's a huge amount of money made each year by preparing taxes for people too intimidated by the complexity to DIY it. So they ally with the generically antitax side to keep their business going.
For more complex cases where you have more deduction and income sources the government doesn't really know all the individual setups you may or may not qualify for and they only audit a small percentage of filers every year.
The reason it's been blocked is a mess of ideological and economic. Ideological from people who interested that want to make taxes more annoying so people are generally more anti tax and then they get elected and make cuts to the top percentages/businesses permanent while the tax cuts for the majority of citizens are temporary. This sets up a debt crisis when those 'temporary' cuts are also extended they can use to leverage for government cuts. On the economic side there's a huge amount of money made each year by preparing taxes for people too intimidated by the complexity to DIY it. So they ally with the generically antitax side to keep their business going.
[0] https://www.irs.gov/statistics/soi-tax-stats-tax-stats-at-a-...