In the simple case of working for one employer all year, no complicated investments or other income, standard deductions, your tax filing in the USA is equally simple and you can complete it in 15 minutes on paper for the cost of a postage stamp.
There are many reasons the US tax situation is complicated. Among them are that it's used to incentivize behavior (tax credits or deductions for various things), there are people invested in it being complicated (tax prep industry), but a big one is that if your situation is complicated, the IRS simply does not have the information it needs until you report it.