> Instead of the US government acting like every other 1st world government and giving us a pre-calculated tax bill since they already know what we owe
They don't know what a given taxpayer owes. They can estimate based on various filings, but there is some stuff that is only reported by the taxpayer when filing. That said, it isn't an excuse to push all the work onto the taxpayer when almost all of what a typical taxpayer needs to fill out could be pre-populated.
> we're forced to spend hours tracking down documents and hoping we didn't mess up and get audited
That the IRS audits taxpayers is evidence that it doesn't ever conclusively know what some people were supposed to pay in a given year, let alone by 15APR of the following year.
They don't know what a given taxpayer owes. They can estimate based on various filings, but there is some stuff that is only reported by the taxpayer when filing. That said, it isn't an excuse to push all the work onto the taxpayer when almost all of what a typical taxpayer needs to fill out could be pre-populated.
> we're forced to spend hours tracking down documents and hoping we didn't mess up and get audited
That the IRS audits taxpayers is evidence that it doesn't ever conclusively know what some people were supposed to pay in a given year, let alone by 15APR of the following year.