Why did the Treasury sharply limit I Bond purchases? [Forbes]

The Treasury Department has been trying to push the investors with the big money balances over to putting the money into T-bills, notes, and bonds and away from Savings Bonds.  Savings Bonds are now seen as something that targets the person with little money to invest.  Since it carries tax deferral properties unlike the other government securities, they don't want the rich investor to benefit from it.  They want to limit the money that you can keep shielded from taxes.