Seems like getting to a point where ~75% of the population didn't need to file would be doable if there was enough motivation for it. If your only income is on a W-2, and your only mortgage / banking / trading is with U.S. companies like Chase or Morgan Stanley, no reason that couldn't all be done for you.
Most brokers send all the info to the IRS, but there are some that get wrong cost basis for ESPP (Fidelity looking at you) and so you’ll have to rectify that too. But those things should spit out a number that gets adjusted from the IRS number.
I had a friend in college who hated doing taxes so he spent 5 min putting whatever numbers into the forms.
A few months later the IRS sent a "your filed incorrectly, here is the corrected return" and he'd be like "cool".