Because most people don't know how simple doing their own taxes are. This is aided by a few people who have a complex situation and would have to have a real accountant do their taxes in every country.
But it’s typically not simple. People often have some kind of life complexity that makes their taxes hard to confidently self-navigate here in the U.S.
Receiving government assistance? Some kinds are taxable, some aren’t.
Moved states? You have multiple state filings now.
Got married? divorced? Splitting custody or property? Special tax forms to fill.
Native American? Veteran with disability? Senior? Student with loans? Bankruptcy? Freelance income? Etc.
Normal life events turn into tax complexity consequences. And without expert help, it’s hard to know if you’re doing your taxes correctly, which adds stress and time.
> Receiving government assistance? Some kinds are taxable, some aren’t.
One would think that the government should know what government assistance you're getting. In any case, taxable benefits get reported to the IRS automatically on form 1099-G.
> Moved states? You have multiple state filings now.
Arguably irrelevant. You can change how filings work federally without changing how state filings work. Perfect is the enemy of good, etc.
> Got married? divorced? Splitting custody or property? Special tax forms to fill.
Sure. Sometimes you have life events that happen where you'll need to make adjustments. Such possible events can be mentioned in the letter / email you get from the IRS, with details as to how to adjust the filing. This is typically how it's been done in other countries with automatic filing.
> Native American? Veteran with disability? Senior? Student with loans? Bankruptcy? Freelance income? Etc.
Income typically gets reported to the IRS on a 1099 or a W-2.
Loan interest gets reported to the IRS on 1098-E, so the deduction could be automatically calculated.
Presumably the IRS would know if you previously filed a tax exemption and could assume that hasn't changed if it's based on things like having registered membership in a federally recognized tribe. Even if you haven't filed that exemption before, presumably the government would know that you registered the membership.
The government knows your birth date so presumably they'd be able to calculate when you become a senior, where that's relevant.
Bankruptcy is one of those special cases that I'd expect would be an exception case where you'd need to adjust the filing (and your trustee would probably help with that).
Most people don't have special cases that require changes. The IRS already has a shockingly large amount of data on people. I encourage you to try getting your tax transcript some time[1], it should be illuminating.
