This isn't how most file.

Also, the way it works is that you still have the option of doing it yourself. But by default, done for you.

That's like saying someone in Google is analyzing your web searches in order to show you ads.

The usual proposed method would be the IRS calculates what you owe based on the standard deduction because they don't know about most donations or possible deductions.

They'd just assume you want to take the standard deduction--which isn't a bad assumption for a lot of people these days.

My taxes are admittedly at least somewhat complex but, even if I did them myself, I'm not sure how much effort it would save if I had to do a bunch of additions and corrections. Pre-filling would mostly be useful if you could just check your W2, maybe a 1099, some things like dependents, sign it, and file it.

They're already doing that