Much of the complexity is to close loopholes. Many things in the tax code start out fairly simple, then people find ways to use them in ways that were not inten

Much of the complexity is to close loopholes. Many things in the tax code start out fairly simple, then people find ways to use them in ways that were not intended, and then the simple thing becomes complex as additional rules are added to try to fix that. This can iterate and what started out as a couple of sentences that most people knew what they intended becomes a few pages of convoluted rules.