That is currently the legal responsibility of the financial institutions (for payments over a certain amount), not the ACH network. The ACH system doesn't have information like SSNs or EINs to associate with individual payments.
Does FedNow have a plan to start gathering and requiring that information from depository financial institutions just to do a simple bank transfer?
That's not to say it wouldn't be impossible to automate our taxes, but we'd probably want to tweak quite a few things in the tax code if we wanted to make automatic filing work without either being onerous or inaccurate.
A very significant number of people take the standard deduction and only include data in their return that has already been provided to the government by their employer and perhaps their brokerage and retirement management firms.
But that wouldn't be a system that would be ...
> the end of the story for those of us not running a business.
as claimed above