Seawolf was projected to be the most expensive ever built, with a total program cost for 12 submarines estimated in 1991 at $33.6 billion in current dollars. As many as 29 submarines were planned. The Navy's plans for Seawolf would have resulted in spending 25 percent of the Navy's shipbuilding budget on a ship that was designed for threats that vanished with the end of the Cold War.

Two Seawolf Class submarines were authorized by Congress, which in 1995 agreed to terminate the program at three boats. President Clinton endorsed the construction of SSN-23 as the most cost- effective method of retaining the vitality of the submarine industrial base while bridging the gap to the future New Attack Submarine. The Fiscal Year 1998 $153.4 million budget request was the final increment of funding required for the third SEAWOLF to complete the program.

https://man.fas.org/dod-101/sys/ship/ssn-21.htm