As bad as the IRS is, an expanded Bureau of Alcohol, Tobacco, Firearms, and Everything Else Sold Under the Sun would be far worse. Give me a flat income tax any day over a national sales tax.
You may believe this is the best solution, but notice... Your mother makes $ 25,000 and spends $ 22,000 on medical expenses each year. You help out to keep her alive. You give her $ 10,000 of your $ 45,000 salary. Your great idea of a flat income tax (15%?, 10%?) leaves her with $ 0 after paying your $ 2,200 tax (living on your donation) and you with $ 30,500 (or less) to feed your family. How's that working for you?
The current tax system began with a a "flat tax". Over time, the needed exceptions folks noticed became "deductions" or "exclusions" or "credits". Now we are here. If we took your advice, we would dump this system and slowly return to it at a cost of billions to re-create the laws which are now in place.
The vast majority of the tax law is not about ordinary folks. That might occupy 100 pages. The books are filled with international taxation rules/regs to stop Toyota from taking all their profits to Japan. Or Steinbrenner from passing the Yankees free of tax (oops, that already happened).