There are exceptions to the levying of the penalty for underpayment. You may have qualified for one of these or you may have flown under the radar and just gotten away with it because you weren’t caught. In either case, you are incorrect. Tax on income is due when the income is earned. Automatic withholding for wages makes this moot for most. The IRS allows taxes to be paid quarterly for income not subject to automatic withholding. The end of year return is NOT your tax bill for the year. It is an adjustment to account for overpayment or underpayment of taxes throughout the year.
It is still a scam. You know when withholding came into being, W.W. II. Was invented by the CFO of Macy’s to help with the war effort, primarily to not only get taxes before they were really due but also to sell War Bonds. The system worked so well it was kept. It is extortion pure and simple to get tax money before it is actually due. I really don’t care if I pay a penalty, no taxes due till the due date.
You see, we the people, put up with this abuse, along with many others and we shouldn’t.