While we're fantasizing, here's one: The government already gets all the same forms I do. They already do all the calculations and will call me out on it if I make a mistake.
How about they just complete the form and send me a check or a bill?
It's totally possible, but it will never happen as long as there are tax-prep lobbyists throwing cash at all our elected officials.
As things stand today, the IRS doesn't know nearly enough about U.S. residents to do most people's tax returns. They have no idea what filing status you're going to use this year; whether you are supporting children or a disabled relative or are an in-home caregiver for someone; whether you installed solar or bought an electric car; or whether you have medical expenses, pay property tax, or made charitable contributions; or whether any of a thousand other situations applies to you.
Most of the time spent on doing tax returns is not on calculating income but on handling credits, deductions and exemptions. Even if the IRS told everyone what all their reported income was, for most people it would still take just as long to do a tax return as it does today.
If you want an automated tax system, then either you have to create a stand-alone social safety net and remove all that stuff the tax code (as most other developed countries have done) or you have to authorize the Feds to collect a whole lot more info on everyone.