And there's nothing wrong with making money on opportunity provided by the government. The periodic auction of treasury securities lets Wall Street firms do just that. Without the Wall Streeters, the debt securities wouldn't get circulated. The peril in the Social Security reform, however, is highly specific. So there's no need to create government-managed funds.
Transaction fees remain.
These are typically minute, and index funds don't trade much. Bush's critics of the moment typically concentrate their fire on the way that his plan will take money away from present obligations of the Social Security program. There's plenty of money for the moment, however. And, without reform, the Social Security system will go bust. Some reform like Bush's is inevitable - inevitable, that is, unless we want disastrously higher FICA taxes.