The whole purpose of IRAs is to encourage regular people to save for retirement. It was not meant to provide billionaires tax loopholes to avoid paying millions or even billions of dollars in taxes.
It's kind of like playing a game with someone. 99% of the people are following the rules and then some weisenheimer comes up with an idea that while technically not breaking a rule goes against the spirit of everything that the game stands for. What happens in that instance is the other players of the game will say, "Nice try, but no." This is what Congress is doing.