> Americans on the whole don't trust their government quite a lot. If the government just said "you owe X in tax this year", nearly everyone's knee jerk reaction would be that the government is overestimating and cheating them.

That's why most governments that do self-declaration services make it so you can review what tax rules they based amounts off of. It's not like tax law is super easy elsewhere and without complications. I should never have to pay a fee just to declare taxes to reconcile things for the IRS. That is a basic governmental responsibility to give me that service for free.