No they don't. There's a gazillion things you could do or claim to lower your tax bill.
Moreover, if you set up all yoyr withholdings correctly then you do not need to file anything. You only need to file if you owe (ie you set up withholding wrong) or want yoyr money back (ie your withholding was wrong)
That is not true. You're generally required to file a tax return if your income is over 12K, depending on your filing status and various other rules, regardless of if you owe money or are owed a refund.
That's the problem. There shouldn't be a gazillion things, and the fact that there are is a major reason why rich, savvy, and unscrupulous people are able to game the system while average people pay full freight.
Moreover, if you set up all yoyr withholdings correctly then you do not need to file anything. You only need to file if you owe (ie you set up withholding wrong) or want yoyr money back (ie your withholding was wrong)