WASHINGTON (Dow Jones)–The federal rescue of the U.S. financial system is likely to cost far less than initially anticipated, partly because the government’s foreclosure-prevention programs have “largely failed to get off the ground,” a new report says.

The rescue, launched by the Bush administration at the height of the 2008 financial crisis, “will cost less than expected, in part because it will accomplish far less than envisioned for American homeowners,” a congressional panel said in its final report on the government’s Troubled Asset Relief Program.

The U.S. government’s Wall Street bailout, initially forecast to be as large as $700 billion, …