They’ve actually been trying to do this for years. There were actually a couple years of tests out in California I think. However, there are two big lobbies that always put a halt to it, tax preparation services (H&R Block, Intuit, etc.) and groups that want taxes to be a pain in the ass so we’ll all bitch about them.

Check out this episode of Planet Money if you want to learn more:

Planet Money - Tax Hero

They already know how, it's been blocked as far as i'm aware by Tax return companies.

I think they already do in a sense; that's the standard deduction. If you want to maximize your returns you might be better off itemizing though, and that option is what makes everything complicated (I suspect they'd have a hard time sending you a bill for everything you itemize... I don't know that they really know everything you could itemize; I think that really only comes up when it's suspicious/you get audited).

i.e., if they did that, you'd basically get fewer options, and maybe less money back(?)

https://youtu.be/Vu3T4ZXzOyw

He explains it a little better

I don't think sending you a bill would work for most people, since they don't know how much you owe until you tell them whether you're married, have dependent kids, have a mortgage, etc. These are things they need to verify every year, so you will always need to send them something every year.

That said, they could certainly make the process simpler.

Oops, accidentally lost all the tax documents of all the rich people. Nothing to see here.

Welcome to (let's be honest, Republican) policies that cut "in-house" staffing for decades at various federal institutions, instead outsourcing important work to contractors, under funding of important projects, and general "backwards" operation.

And they do. My family member still insists on only submitting thier taxes by snail mail. For 2021, the IRS lost the original, required a second submission (of original documents, lol), and then lost that one. In the end, they had to get an advocate to help them submit a third, and final return.

At least they didn't owe, or I'm sure they would have been in big trouble. But of course the IRS sending the refund check over a year late, has no repercussions...