You're mixing a few things together here...
1. Remote autonomous sensors will be the tripwire that indicates something needs further tracking/investigation.
2. An ASROC is a weapon you fire once to hit a target, like a harpoon, NSM, or ESSM, they don't loiter waiting for a target to appear and return to the launcher if nothing is found. Loitering munitions, UAS, and missiles are different things, despite having some similarities.
3. Systems like the MQ-9B are uncrewed, but human controlled. Exactly what I was talking about sending out to engage a suspected target that has been detected/verified. A MQ-9B doesn't need a 1000km ASROC to do it's job, because it flies close enough to engage targets from within the weapon's effective range.
Long range weapons for striking targets unlikely to move, or that can be required after they move makes a lot of sense, but specifically in the context of ASW, super long range weapons make no sense.