If the US has submarine locators (or even a theory or a work-in-progress), it has to keep them secret. The DoD or Navy might not want to reveal them to any Representatives. This would prevent them from explaining to those Representatives why submarine budgets should be lowered in favor of something else.
A submarine locator doesn’t stop submarines by itself; you still presumably need to bring ships and/or planes to where the submarines are. If you do this ahead of time and just keep following the enemy subs around, they are likely to notice, and you will lose strategic surprise. The US has a lot of fleet elements and air bases around the world (and allies), so it plausibly has an advantage over its rivals in terms of being able to take out widely dispersed enemy submarines all at once.
Even if others also secretly have submarine locators, there may be an additional anti-sub-locator technology or strategy that the US has developed and hopes its rivals have not, which would keep US submarines relevant. Building a sub-locator might be necessary but not sufficient to building an anti-sub-locator.
Epistemic status: wild guessing:
If the US has submarine locators (or even a theory or a work-in-progress), it has to keep them secret. The DoD or Navy might not want to reveal them to any Representatives. This would prevent them from explaining to those Representatives why submarine budgets should be lowered in favor of something else.
A submarine locator doesn’t stop submarines by itself; you still presumably need to bring ships and/or planes to where the submarines are. If you do this ahead of time and just keep following the enemy subs around, they are likely to notice, and you will lose strategic surprise. The US has a lot of fleet elements and air bases around the world (and allies), so it plausibly has an advantage over its rivals in terms of being able to take out widely dispersed enemy submarines all at once.
Even if others also secretly have submarine locators, there may be an additional anti-sub-locator technology or strategy that the US has developed and hopes its rivals have not, which would keep US submarines relevant. Building a sub-locator might be necessary but not sufficient to building an anti-sub-locator.